Fliers' alert: United, Continental merger comes Saturday

— -- United and Continental Airlines will switch to one computer system on Saturday in one of the final steps to operating as a single airline.

Starting at 2 a.m. ET, workers will complete the process of transferring customer and reservation information from United's Apollo computer system to Continental's Shares system.

United spokesman Rahsaan Johnson says the conversion will be done in time for travelers on the East Coast to check in for their Saturday morning flights. "We don't expect any interruptions in operations or customer service," he says.

Analysts say any number of glitches could occur, causing problems such as lost reservations and misplaced luggage. Travelers with reservations involving United and another carrier should be particularly on guard.

"If I were going to the airport, I would print my boarding pass beforehand at home or the office or I would get the bar code delivered to my mobile device beforehand," says Robert Mann, an airline analyst at R.W. Mann & Co.

Other airlines have hit turbulence when switching computer systems. When US Airways and America West combined their systems in 2007, the computers failed to communicate with airport kiosks, causing long lines and delayed flights. Customers had trouble making and changing reservations when Virgin America moved to a new system last fall.

Mann says such problems usually occur when the changeover has been rushed. As for United Continental, he says, "They've had all kinds of time to do this. I have no reason to believe this hasn't been well-scoped or planned."

United and Continental announced their merger in May 2010 and received a single operating certificate from the Federal Aviation Administration in November. For customers, however, the integration of the computer systems is the most important part of the merger.

The airline has had four trial runs in the new system, and extra staff will be on hand for the first few weeks of the changeover, Johnson says.

Also this weekend: Continental's website will become a new United.com.

All Continental signs also will be removed from airports. Continental flights will be recoded to United flights, and the airlines begin a joint MileagePlus frequent-flier program.