MIAMI— A well-effected merger integration day should be completely transparent to the traveler. American Airlines gets to put that theory to the test this weekend when the US Airways reservations and Passenger Service System (PSS) is retired and the entire company’s operation is consolidated on to the American Airlines PSS platform. Looking back at this merger’s history as well as that of other mergers gives some insight as to what travelers can expect this weekend.

US Airways has some history when it comes to merger integration days, history it would likely choose to suppress if it could. The America West integration was nothing short of a complete mess, with kiosks across the network failing and missing reservations for thousands of travelers. It was, as integration efforts go, a disaster. And current CEO Doug Parker also oversaw that effort, providing plenty of opportunity to learn and not repeat the mistakes. United Airlines and Continental’s integration day was not quite as bad, but it was also not especially smooth. Similar platform integration challenges and training issues left many travelers in the lurch on that fateful March weekend 3.5 years ago. Both of those transitions were accomplished through a “shot-gun” approach to the work, fully maintaining the legacy systems in parallel until the appointed hour when all the data on the platform being retired was migrated to the PSS being kept. Recent history suggests that for a major airline migration effort that’s a bad plan.

The Delta/Northwest integration was run as a “drain down” process. Some months in advance a deadline was set and all new bookings for travel after the integration date were handled only on the new platform. As the integration date approached fewer and fewer reservations existed on the old system meaning there was not as much effort required to retire it; for the vast majority of travelers on the integration day there is nothing to migrate. For this week’s merger American Airlines is choosing that approach. American’s CIO Maya Liebman previously suggested that fewer than 5% of bookings will need to be migrated on integration day.

The combined company has been pushing more and more reservations into American’s SABRE system for months now. It finally disabled the ability to book on the US Airways side of the operation three months ago and has been pushing customers into the American platform since. While that avoids many potential pitfalls the company still faces challenges.

Airport agents are the other main group which is affected by any such migration and the different systems can create havoc when those agents are called upon to help passengers. For this integration there are two factors working in favor of the company. First, the larger half of the company is the legacy American Airlines group which means the training curve to use the new system is much lower. And for the legacy US Airways side of the operation the company has built an overlay on to SABRE which mimics the GUI those agents are used to working with. The United/Continental merger did not have such an overlay available for the legacy United employees who switched back to a text-based interface during that integration; it did not go well.

Industry pundit Henry Harteveldt suggests that the company has made the correct choices thus far in the planning process, “The approach is very smart. I like the draw down strategy and that they’re going on to Sabre. They’ve learned lessons from previous mergers. It’s very smart that they created a US Airways UI on top of an existing AA platform.” And, even considering the IT hiccups along the way (some customer service functions remain disabled on the front-end even today), it appears that American has put itself in a position to succeed. Keep your eyes peeled on Saturday morning to see just how well it works.