BOSTON, Feb 2 (Reuters) - A U.S. appeals court on Friday said it would hear arguments in June in a bid by JetBlue Airways and Spirit Airlines to overturn a judge's ruling that blocked their $3.8 billion merger, an expedited schedule that was nonetheless slower than what the companies wanted.

The airlines earlier this week had asked the Boston-based 1st U.S. Circuit Court of Appeals to take up their appeal on a speedy timeline so it could hear arguments in May and rule before a July 24 deadline their merger agreement provided to close the deal.

The U.S. Department of Justice, which sued to block the deal, opposed the airlines' proposed schedule and pushed for June arguments, saying closing dates are often renegotiated by merging companies to give courts more time to hear antitrust challenges.

The airlines said that argument was "divorced from commercial reality," as the merger was dependent on $3.5 billion of financing JetBlue obtained that would also expire on July 24 unless its lenders agreed to an extension.

Under the order issued on Friday, the companies' initial brief would be due on Feb. 26, with the Justice Department response set for April 11. The case would be fully briefed by April 25.

"We contemplate argument during the court's June sitting," the 1st Circuit's order said. "Extensions will be strongly disfavored."

The companies and Justice Department did not immediately respond to requests for comment.

The appeal flows out of an antitrust lawsuit by the Justice Department and the Democratic state attorneys general from six states and the District of Columbia, who argued the merger would lead to fewer flights and higher prices for millions of Americans.

Following a non-jury trial, U.S. District Judge William Young on Jan. 16 sided with the Justice Department, finding that the deal would harm consumers. He said it would eliminate Spirit's low fares and its ability to put pressure on other higher-priced airlines. (Reporting by Nate Raymond in Boston and David Shepardson in Washington; Editing by Bill Berkrot)