Southwest Airlines planes clip wings at Oakland International Airport

OAKLAND INTERNATIONAL AIRPORT (KGO) -- Southwest Airlines is investigating a collision between two planes at Oakland International Airport.

The wings clipped Sunday as a 737 loaded with passengers tried to depart for Orange County.

Southwest flights make up two-thirds of the more than 300 daily flights in and out of Oakland International Airport.

While these types of collision are rare, there was a similar incident in June involving Southwest planes at the Bob Hope Airport in Burbank, Calif. earlier this summer.

The airport experienced long lines at the ticket counter Sunday night after the crash.

"We were backing out just about 10 seconds from the gate and heard a loud popping noise and basically a jolt," said Manas Gowd, a Southwest Airlines passenger.

Passengers snapped photos of a snapped wingtip after after Southwest flight 2674 tried to depart from the gate around 10:30 p.m.

"We looked out the window and saw a chunk of the wing tip on the right side come off and you could tell both planes had touched, well really clipped each other, because the movement wasn't natural," Gowd said.

"It was just the scraping, like if you were in an auto collision," said Lana Alber, a Southwest passenger.

Oakland International Airport referred to the airline for comment regarding the incident.

Southwest Airlines has released few details, but said both planes involved are out of service and will undergo maintenance checks.

A spokesperson would not answer questions regarding who was in control of the planes involved, pilots or ground crews.

"We had to flag down a flight attendant and say look out there that's not supposed to look like that," Gowd said.

Both the crash at Oakland and Burbank involve the plane's winglets, which are extensions added for efficiency starting in 2000. The winglets increase the total wingspan by about five feet according to Boeing, the manufacturer.

Oakland airport officials say those extra few feet should not be a factor in the collision, saying lanes are striped based on the dimensions of the planes.