United Airlines
In December, Chicago Breaking Business reported that United switched from its Apollo reservation system to Continental’s reservation system which is provided by Hewlett-Packard Co. Reuters

United Airlines' recent major computer systems failure for approximately five hours on Friday night caused major delays and cancelled flights throughout its system.

United said that the system failure affected departures, airport processing, and reservations which caused flights not to be able to take off from some locations including its hub in San Francisco International Airport (SFO)

The airline cited a network connectivity issues as the reason for the computer systems failure which were fixed through troubleshooting procedures

United Airlines and Continental Airlines closed a merger deal several months ago on October 1, 2010. Since then, the merger went through relatively smoothly through federal regulators and the company quickly named Continental CEO Jeff Smisek as the new CEO of the combined airline.

The two airlines then began integrating their computer systems.

In December, Chicago Breaking Business reported that United switched from its Apollo reservation system to Continental's reservation system which is provided by Hewlett-Packard Co.

The systems integration has noticeably been ramped up in the past month.

For example, on June 9 United changed its seating chart system to match its row numbering with Continental.

More noticeably, United Airlines changed their boarding procedure, first doing away with its zone boarding procedure and boarding by row. The company then backtracked on the changes and re-instated a modified zone boarding system on June 8 because of customer feedback.

At the time, United spokesman Scott O'Leary mentioned the company would do some field testing on the procedure saying, We're committed to making this process work, and we hear you loud and clear.

On June 15, the airline aligned its check-in requirements for flight making cut-off times for check-in the same for both airlines. Though this was a minor change, the check-in systems had to be updated in order to accommodate the new policy.

Finally, on June 16, just one day before the computer systems failure, the airline's website united.com experienced an error where it charged Close-in Ticketing Fees when they were not applicable. Close-in Ticketing Fees was one of the fees which the two airlines recently aligned for its award tickets.

At the time, company representative Shannon Kelly said, We are working through a process to automatically refund the fee in the cases.

United Airline has not elaborated further on the specific reason for the computer systems failure. Continental Airlines did not experience the same problems that United had.

However, it's clear the combined airline is making many behind the scenes changes to its computer system as it moves towards being one airline.

Whether or not the merger related computer system changes had any impact on the major computer systems failure yesterday remains to be seen. However, it's clear the delays and cancelled flights that were a result of the failure, was a major black eye on a company that wants to show a good image to customers as the two airlines merge into one.