Whether for business or leisure, there are a huge number of people flying in and out of San Francisco International Airport (SFO). A recent report found travel-related spending in California hit $157.

In a statement, the Federal Aviation Administration said United Flight 863 heading to Sydney, Australia and United Flight 877 bound for Hong Kong were the two planes involved. Flight 863’s left wingtip collided with the right wingtip of Flight 877 about 12:35 a.m., the FAA said.

The emergency at the bayside air-travel hub began about 8:30 a.m., when a passenger aboard Honolulu-bound Hawaiian Airlines Flight 15 was overheard "making a threat to the safety of our aircraft."