NEWARK, New Jersey (Reuters) -United Airlines CEO Scott Kirby said on Tuesday his company is not going to make a bid for bankrupt Spirit Airlines' assets if they become available.

Spirit filed for bankruptcy protection last month for the second time in a year after a previous reorganization failed to put it on firmer financial footing. The discount carrier's restructuring will involve shrinking its network and fleet, which is expected to put a variety of its assets up for grabs for competitors.

Kirby, however, told Reuters that Spirit's airplanes, slots and routes "just don't work" for the Chicago-based airline. He said it would take two to three years and cost $15 million per airplane to reconfigure the budget airline's fleet, making it "impractical" for United.

Similarly, there are not enough gates for United in Spirit's key markets like Fort Lauderdale in Florida, he added.

"It's not in our wheelhouse," Kirby said in an interview. "And so we're not going to try to do that."