Maybe you should fly Southwest Airlines instead. Oh wait....
Southwest computer glitch. Flights delayed/ canceled June, 2013
http://www.reuters.com/article/2013/06/22/us-usa-southwest-flights-idUSBRE95L08520130622
Southwest computer glitch. August, 2012
http://www.foxnews.com/us/2012/08/04/southwest-airlines-says-computer-glitch-caused-ticket-woes/
Southwest maintenance glitch, February, 2015
http://www.usatoday.com/story/news/2015/02/25/southwest-inspections-737-rudder-grounding-embry-riddle/24000203/
Maybe American Airlines? Oh wait...
American Airlines computer glitch, grounds all flights, April, 2013
http://www.theverge.com/2013/4/16/4231552/american-airlines-grounds-all-flights-after-experiencing-nationwide
American Airlines computer glitch delays flights, April, 2015
http://aviationblog.dallasnews.com/2015/04/computer-glitch-delays-american-airlines-flights-tuesday-night.html/
Maybe Delta? Oh wait...
Delta Airlines computer glitch. February, 2015
http://www.usatoday.com/story/todayinthesky/2015/02/02/delta-air-lines-computer-glitch-frustrates-fliers/22771143/
Delta Airlines computer glitch grounds flights, May, 2004
http://www.cnn.com/2004/TRAVEL/05/01/delta.delays/
There’s always Alaska...
Alaska Airlines, flights canceled due to computer outage, March, 2011
http://www.komonews.com/news/local/118735944.html
Alaska Airlines computer glitch, October, 2012
http://www.kpho.com/story/19768274/alaska-airlines-recovering-from-computer-glitch
Alaska Airlines computer glitch, June, 2013
http://www.kirotv.com/news/news/alaska-airlines-flights-delayed-due-brief-computer/nYY4b/
And Virgin...
Virgin Airlines computer glitch, August, 2013
http://www.abc.net.au/news/2013-08-06/system-glitch-hits-flights/4869316
I ran out of time...there are many more. :)
Perhaps the computer excuse applies to all airlines as you suggest.
But don’t take it from me, JD Powers shows United to be near the bottom in customer satisfaction in 2015, again:
http://www.jdpower.com/press-releases/2015-north-america-airline-satisfaction-study