CHICAGO, Feb 20 (Reuters) - United Airlines will rely more on Boeing 737 MAX 9 and Airbus A321 aircraft in the absence of MAX 10 to pursue its growth plans, Chief Financial Officer Mike Leskinen said on Tuesday.

A mid-air

emergency

last month on an Alaska Airlines 737 MAX 9 has raised new doubts over certification of the already delayed MAX 10. United has ordered 277 MAX 10 jets with options for another 200.

While United has not cancelled the order, the airline has

removed

them from its internal plans. That has raised questions about the carrier's ability to grow domestic capacity by almost 30% by 2026 under its

"United Next" plan

.

At Citi's industrial conference, Leskinen said the airline would not be able to grow as fast without MAX 10.

"What you're going to see now is much more MAX 9 and 321 aircraft," he said. "The mix of which I don't know yet. It depends on the prices."

Reuters last month reported that United had

approached

rival Airbus about buying more A321neo jets as possible alternatives to its MAX 10 order.

Leskinen said United is "deeply disappointed" with Boeing due to aircraft delivery delays. The Chicago-based airline has options to mix some additional Airbus product into its "Boeing heavy fleet" and extend the life of some planes that are ready to retire, he said. (Reporting by Rajesh Kumar Singh; Editing by Nick Macfie)