Computer systems went offline for about three hours Saturday afternoon, said Kevin Simmons, director of technology support for SkyWest.
The power outage crashed telephone and computer systems, making the airline unable to dispatch flights.
SkyWest President Ron Reber said about 130 of the airline's 1,628 Saturday flights were canceled, including 29 in the Salt Lake City hub, 20 in Denver and 34 in San Francisco.
Reber said between 40 and 50 flights were also delayed, affecting more than 1,000 passengers throughout the country.
SkyWest tried to rebook most flights, including many through its mainline carrier, United Airlines. Some passengers were given hotel and flight vouchers, said spokeswoman Marissa Snow.
''Our first concern is accommodating our passengers,'' she said.
The company believes a lightning strike touched off a series of technical failures.
''We don't know that it struck the building,'' Simmons said. ''We just know from the people that were there that there was a strike nearby.''
The building's internal generators kicked in when power cut out from city electrical lines. But when power was restored, it unexpectedly tripped a breaker usually reserved for maintenance on the system.
Only battery power remained to keep the building's internal power system running.
When the batteries were drained, everything ''shut down in a hard way,'' Simmons said. ''Just like pulling the plug.''