SFO ATC Clears Two United Planes To Take Off At Same Time, Then Denies It

An air traffic controller accidentally cleared two planes to take off on parallel runways around the same time, putting them on a course dangerously close to one another. Perhaps what’s most noteworthy here is how the air traffic controller then acted confused about how this happened…

“I don’t how you guys both got takeoff clearances”

This incident happened shortly after midnight on January 24, 2026, and involves two aircraft:

• United flight UA2621 was operated by a Boeing 777-200ER, and was scheduled to operate to Houston (IAH)
• United flight UA2312 was operated by a Boeing 737 MAX, and was scheduled to operate to San Jose (SJO)

What happened here is pretty straightforward. Flight UA2621, the 777, was cleared for takeoff on runway 1R. Then a moment later, flight UA2312, the 737, was cleared to line up and wait on runway 1L, which is parallel to 1R. Around 30 seconds later, the 737 was cleared for takeoff.

So here’s where the issue arises — the 777 that was cleared to take off still had to actually get onto the runway, which takes a little time, given the taxiway configuration around 1R. It took the plane around 30 seconds to get into position and start its takeoff roll… roughly coinciding with when the 737 was cleared for takeoff.

The two planes started their takeoff rolls around the same time on parallel runways, and they had the exact same departure clearance. For obvious reasons, that’s not going to end well.

After both of the planes were airborne, the controller clearly realized that something wasn’t right, so he gave the planes vectors to separate them a bit more.

Oddly, the controller then said “yeah, I don’t know how you guys both got takeoff clearances, but that did not happen.” Which is, you know, ironic, because he was the one to give them takeoff clearance, and it absolutely did happen.

After being handed over to the departure controller, one of the pilots of UA2621 checked in to try to figure out what happened, since they had been given the SSTIK departure, but were instead flying on an assigned heading.

The controller confirmed that “the tower said there was an issue with the departure, and you rolled and another one rolled right behind you, so you got to get separation.” The pilot responded with “okay, no problem it’s just that he sounded a bit alert, that’s all.”

We all make mistakes, and at least he caught it fast

Arguably our air traffic control system relies a little too heavily on human intervention rather than automation, when you consider the need to be right 100% of the time.

Presumably the tower controller wasn’t thinking of how long it can take to taxi onto runway 1R from the taxiway the 777 was on, and wasn’t properly tracking that plane’s location while giving clearance to the 737 on runway 1L.

Though perhaps what’s most puzzling is how maybe a minute after giving both planes takeoff clearance, he claimed that he had no clue how the second plane was cleared for takeoff. I guess we all have some occasional short term memory loss, but that’s a pretty major detail to forgot.

Ultimately kudos to all parties involves for their professionalism, and the controller deserves credit for how quickly he caught the mistake, even if he didn’t realize he was the one who caused it. I’d certainly be forgetful if working at midnight (not that this is an excuse).

Bottom line

Two United jets ended up doing near parallel takeoffs at SFO, after a controller didn’t leave enough spacing between the two planes. A 777 received takeoff clearance first, but it took a bit longer for the pilots to taxi the plane onto the runway. Then a 737 was cleared for takeoff a short while later, but it was already in position on the runway, at that point.

Mistakes happen, though what makes this unusual is how the controller then denied that the second plane had been given takeoff clearance, as obviously he wasn’t expecting such a close call.

What do you make of this SFO takeoff incident?