TULSA, Oklahoma - One of the largest planes ever built left Tulsa International Airport just after noon Friday.

The Antonov An-124 had been sitting on the tarmac at the airport for a week. This particular jet is operated by Polet Airlines, a cargo company based in Voronezh, Russia.

Citing security concerns, the company that chartered the huge jet didn't want to release any details about what it's carrying or where it's going.

That didn't stop aviation buffs from around Tulsa from waiting at the north end of the airport to watch the 4-engine jet roar into the Oklahoma sky.

The aircraft is 226 feet long and has a wingspan of 240 feet, dwarfing the commercial airliners that had lined up behind it for their turn to use the runway. Its 68-foot-tall vertical tail towered over the passenger concourse.