MIAMI— The first hope for a revival at MacArthur arrived in March 2012 when US Airways Express, the airport’s only remaining carrier other than Southwest, began daily service from MacArthur to its hub at Ronald Reagan Washington National Airport using 50-seat Canadair Regional Jets. The new service would supplement its existing service to its Philadelphia hub on 37-seat Dash 8 turboprops.

US Airways is the successor of Allegheny Airlines, which provided MacArthur with its first commercial service in 1960. It’s the only airline that has continuously served the airport ever since then, first as Allegheny, then as USAir and eventually as US Airways. The Philadelphia route was all that was left of a once-substantial operation, with service on mainline jets to cities up and down the East Coast. The carrier had actually offered Islip-Washington service in the past, making this more of a resumption of a long-dormant route than a brand-new one.

US Airways and its now-parent company, American Airlines Group, say the route has been a success. According to data filed with the Department of Transportation, it has had an average load factor of 81%, above US Airways Express’ network average; virtually all of this has been local traffic from Islip to Washington or vice versa. (This is in contrast to the Islip-Philadelphia route, which DOT data shows mostly carries connecting traffic.) But as it stands, despite its success —a rare thing at MacArthur these days —the service will end on July 2, 2014.

This is because, as a condition of US Airways’ merger with American in December 2013, the combined carrier was forced to give up 52 daily slot pairs at Reagan National. The arrangement came at the cost of service from that airport to 17 mostly small ones, including MacArthur. (American stresses that all the airports in question will still receive service from at least one of its other hubs, such as Philadelphia in MacArthur’s case.)

However, there is some hope for the future of this route. In March 2014, the DOT issued a request for applications from carriers for a slot pair at Reagan National to be used for service to an airport classified as a medium or small hub or non-hub airport. (MacArthur is classified as a small hub by the DOT, though it is not a hub in the normal sense of the word.) The slots are part of the AIR-21 program, which is designed to ensure service from the congested airport to destinations for which airlines would not otherwise use their valuable slots. American requested that the DOT allocate it the slots for it to continue, or resume, service to MacArthur.

The slot pair in question was formerly allocated to Republic Airlines and used for service on its then-subsidiary Frontier Airlines to Kansas City. Republic has since returned them to the DOT for reallocation as part of its divestment of Frontier, and they have been temporarily reallocated to Southwest for it to continue the Washington-Kansas City service. In addition to American’s application, the DOT has received competing applications from Southwest to make permanent its service to Kansas City, from JetBlue to serve Jacksonville, Fla., and from the newly reincarnated People Express Airlines for seasonal service to Myrtle Beach, S.C. and West Palm Beach, Fla.

In its filing with the DOT, American argues that, “No other U.S. airline is more committed to smaller communities than [American], and this application reaffirms this commitment,”and that out of all those filed, its proposal “would provide the greatest level of public benefits, preserving nonstop service to [Reagan National] for a small community that would otherwise lose it.”

American says that now that low-cost carriers like Southwest and JetBlue have substantial slot holdings at Reagan National, in large part because of American’s own merger-related slot divestitures, their service to mid-sized cities like Kansas City and Jacksonville should no longer receive special treatment under AIR-21, and the program should focus solely on ensuring service to small markets like Islip, even if operated by large legacy carriers like American. The DOT has yet to make its decision in the matter.

Asked why US Airways chose to expand its service at MacArthur at a time when other carriers had reduced or eliminated service, and if American would consider serving the airport from any of its hubs other than Philadelphia and Washington, American spokesperson Matt Miller said, “In short, we are always evaluating markets and looking for opportunities. This was certainly the case back in 2012 when US Airways started the [Washington-Islip] service.”

In July 2013 MacArthur regained service to another former destination, Boston, and gained its first new carrier since 2008 when PenAir, a regional carrier from Alaska, began twice-daily service to Islip on 34-seat Saab 340 turboprops from the Boston focus city it opened in 2012. (That last new carrier in 2008 was Spirit Airlines, which, no doubt at least in part a victim of exceptionally bad timing, served the airport for less than three months before leaving. Spirit had also served the airport in the past, pulling out for the first time in 2001.)

Boston is a destination that several carriers had served from MacArthur in the past, and one to which town officials badly desired a resumption of service. That desire was exemplified by a press release issued when the service was announced in March 2013 in which town supervisor Tom Croci welcomed “the long-awaited return of service from MacArthur to Boston.”In the same press release, the town cited a “recent …poll of Long Island corporate travel managers”it commissioned, which “revealed Boston as a primary destination for Long Island executives.

”The press release also stated that the town hoped the service would “present tourism opportunities for Bostonians to Long Island’s rich tourism industry,”perhaps referring to the Hamptons and other popular summertime tourist destinations on eastern Long Island, to which MacArthur is the closest commercial airport.

But for all the optimism expressed by town officials over the new service, PenAir announced on May 20, 2014 that it would end service at MacArthur sometime this summer. Current schedules place the end on July 25, exactly one year after the carrier began serving the airport. PenAir’s chief operating officer, Dave Hall, bluntly told Newsday, “We were losing money. We just weren’t able to get to a consistent operating profit. Unfortunately it’s a business, and that’s how it works.”(PenAir did not respond to our request to comment.) For its part, the Town of Islip blamed the airline for failing on what it claimed was a promising route; airport director Robert Schaefer told Newsday that PenAir “didn’t have reliable flights. They had a lot of cancellations, and they admit that was their problem. We tried our best, but they weren’t filling up the planes.”Schaefer also said the town was negotiating with another carrier to begin service to Boston.

The most recent new service to begin at MacArthur brought not just a new carrier to the airport, but a new type of carrier, and a new destination as well. In December 2013 ultra-low-cost carrier Allegiant began what was initially announced as year-round, twice-weekly service from MacArthur to Punta Gorda, marketed by the carrier as Ft. Myers/Punta Gorda, using 166-seat MD-80s. Announced in August 2013 as part of a major route expansion, the route from MacArthur to Punta Gorda marks Allegiant’s return to the New York City area along with a route from another of the area’s secondary airports, Stewart, to St. Petersburg, Fla.

Allegiant’s previous attempt at competing in the New York City area consisted of a route it operated from Stewart to Sanford, Fla. from 2005 to 2007. It left in 2007 because two larger low-cost carriers, AirTran and JetBlue, both began service at Stewart. Both airlines opted to serve Orlando, the market Sanford serves as a secondary airport. That meant Allegiant would face direct competition, which it typically avoids. Instead, it specializes in infrequent nonstop flights from what it says are underserved smaller cities to leisure-oriented destinations, routes other airlines, with their higher costs, can’t serve profitably.

Both MacArthur and Stewart already have service to several destinations in Florida on Southwest and JetBlue, respectively. The largest Floridian destination to which MacArthur has no service is Ft. Myers, to which Punta Gorda is an alternative, most likely giving Allegiant the reasoning for its choice of these two routes for its return to the highly competitive New York City-area market.

But while Allegiant’s Newburgh-St. Petersburg service will, as announced, operate year round, the Islip-Punta Gorda route ended on May 26, 2014, barely five months after it began. Allegiant says this is only a seasonal suspension. According to Allegiant spokesperson Lindsay Hernquist, “We are happy with the strong demand we have seen for the [Islip-Punta Gorda] route during the winter months,”but “found that the demand …was very seasonal. Instead of discontinuing service from [MacArthur] altogether, we chose to make the flights available when the customers want them.”Hernquist says that the carrier has “seen stronger year-round demand for the [Newburgh-St. Petersburg] route, compared to the [Islip-Punta Gorda] route,”which is why that route will operate its originally announced year-round schedule.

Allegiant has yet to announce exactly when it will resume serving MacArthur. According to Hernquist“the Islip route will resume later this winter,”and an exact date will be available when the carrier posts its winter flight schedule sometime during the summer. But regardless, unlike US Airways Express’route to Washington, which may or may not resume, and PenAir’s to Boston, which is about to end for good, it appears Allegiant’s service from MacArthur to Punta Gorda will return.

None of these routes had the potential to dramatically change the situation at MacArthur. Even if all three had continued indefinitely, they would, together, have represented only a small amount of growth for the airport. And it would have continued to be heavily dominated by Southwest, a carrier that seems unlikely to expand or, more precisely, restore service at an airport that is now of greatly diminished strategic importance to it. But they still represented more new service than MacArthur had seen in years, and more hope for the future —hope that, at least for now, seems to be fading away again.