Shares of Lockheed Martin fell as President-elect Donald Trump tweeted that making F-35 fighter planes is too costly and that he will cut "billions" in costs for military purchases.

Lockheed makes the F-35 one-seat fighter aircraft for the U.S. and is a major defense contractor. The F-35 program made up 20 percent of Lockheed's total revenue last year.

The F-35 program and cost is out of control. Billions of dollars can and will be saved on military (and other) purchases after January 20th. — Donald J. Trump (@realDonaldTrump) December 12, 2016

This is the second time in a week that Trump has blasted U.S. aircraft spending. Last week, Trump tweeted that costs to build new presidential planes by Boeing Corp. were "out of control" and ended the tweet with "Cancel order!"

Representatives from Lockheed, based in Bethesda, Maryland, did not immediately have a comment.

Lockheed Martin Corp. shares fell 2.5 percent to $253 before the stock market open Monday.