Boeing and VietJet signed the provisional order for 100 Boeing 737 MAX airplanes worth almost $13 billion at list prices at the Farnborough Airshow in southern England.

Of these, 80 are the recently launched 737 MAX 10 - the largest version of Boeing's best-selling 737 range - and 20 are the benchmark 737 MAX 8 model.

"The growth is incredibly strong in Southeast Asia," said Boeing Commercial Airplanes CEO Kevin McAllister. "VietJet is a major player there."

The draft deal comes two years after Boeing upstaged Airbus by clinching an order for 100 737 MAX jets during a visit by then-U.S. President Barack Obama.

Until then, VietJet had only ordered planes from Airbus, including a bumper order for 92 jets in December 2013.

However, aircraft finance industry sources have expressed doubts over whether all the planes on order would be delivered on schedule amid a glut of airplane orders in the region.

VietJet CEO Nguyen Thi Phuong Thao insisted on Wednesday the airline would use both the A320 and 737 aircraft in its fleet and would have "no problem" taking delivery.

The companies said VietJet, one of the fastest-growing carriers in southeast Asia, needed the planes to satisfy surging demand on high-dense domestic routes as well as popular routes throughout Asia.

Vietnam's first privately owned airline will become the largest MAX 10 customer in Asia once the deal is completed, with deliveries due in 2022-2025, the companies said.

(This version has been refiled to add full company name, stock code for VietJet in paragraph 1)

(Reporting by Eric M. Johnson; Editing by Jason Neely and Mark Potter)

By Eric M. Johnson