A federal judge who ordered American Airlines and JetBlue Airways to spike their Northeast partnership is giving the airlines more time to unwind the deal.

U.S. District Judge Leo Sorokin in Boston said in an order Monday that the injunction he ordered last month will take effect 21 days after he issues a final judgment imposing terms on the airlines. It’s not clear when that will be.

The airlines had faced a deadline next weekend, just 30 days after the judge’s May 19 decision in favor of the U.S. Justice Department, which sued to break up the deal.

American Airlines CEO Robert Isom said last month that his Texas-based airline will appeal the May ruling. New York-based JetBlue has not indicated whether it will appeal.

The Legislature faces a Thursday deadline to select an August weekend as this year’s sales tax holiday, when the typical 6.25% levy does not apply to most retail items less than $2,500.

Retailers Association of Massachusetts President Jon Hurst said the annual burst of shopping on the weekend without a sales tax generates roughly half a billion dollars in sales, far more than the revenue state government foregoes in those two days.

“We have some members that it’s their biggest weekend the entire year. Others say it’s comparable to either Black Friday weekend or a weekend in December. It literally brings people out to shop when they otherwise would not be spending dollars,” Hurst said.

The House and Senate agreed last year to suspend the sales tax on Aug. 13 and Aug. 14.

Hurst said he’d like to see the second weekend in August — Aug. 12 and Aug. 13 — picked again in 2023 because it “strikes the right balance.”