What American Airlines Passengers Should Know Before Reservations Systems Merger

— -- Saturday is the day of reckoning for many plane travelers and, in particular, American Airlines, which is combining its reservation system with that of US Airways, a process that has traditionally caused major headaches and disruptions for passengers.

If you're flying on American Air this weekend, the airline has some advice to offer. The company has sent email to fliers to help navigate their day of travel, including checking in before heading to the airport and getting your boarding pass on AA.com or the American app as early as 24 hours before departure.

The company also advises fliers to use the same tools to check their terminal and gate before leaving for the airport, and for any last-minute changes or flight notifications.

“If past is prologue, it will be a miracle if there aren't a few air pockets, if not immediately then later on,” George Hobica, Airfarewatchdog.com founder, said. “Airline reservation systems are notoriously antiquated and have been a poor stepchild when in past years scarce funds were allocated to other priorities.”

The combined American Airlines Group Inc., formed after the 2013 merger, says it has spent 22 months "planning, preparing, testing and training for this Saturday."

That’s when all US Airways flights will become American flights.

American doesn’t have the total number of fliers expected this weekend, but the company reduced the schedule by about 200 flights over Saturday and Sunday "to simplify the schedule a little,” a spokesman told ABC News.

The final US Airways flight, Flight 1939, named for the year US Air's predecessor, All American Aviation, launched, left San Francisco today 31 minutes late and headed to Philadelphia.

"More than 50,000 employees have completed over one million hours of training. More than 9,000 computers and kiosks have been tested," the company said in a statement. "We’re committed to getting this right."

But not all airlines have completed a successful reservations system merger. Two years after US Airways and America West merged in 2005, the companies struggled to combine their IT systems.

United Continental Holdings Inc. merged in 2010 and combined two systems in 2012, which caused disruptions for weeks for passengers and employees. At least one carrier, Delta Air Lines, had a "successful" reservations tech merger, according to the Wall Street Journal. That was with Northwest Airlines Corp. in 2010.

American Air said it's prepared for the big move, adding that staffing levels at airports have increased 20 percent, including 350 additional IT technicians at airports and more than 80 American Airlines airport agents to assist at US Airways hubs. The company said it has tested more than 9,000 computers and kiosks.

"We’ll have extra staff on hand at airports and reservations centers, 24/7 command centers, and hundreds of technology workers on Saturday and beyond – all focused on making this a seamless transition for customers," the company said in its statement.

Meanwhile, the US Airways app will be disabled by Sunday and the two frequent-flier policies will fully combine by Saturday.