JetBlue Airways Corp. formally abandoned its pursuit of Spirit Airlines Inc. more than a month after a federal judge blocked the $3.8 billion acquisition on antitrust grounds, Bloomberg News reported. The carriers reached an agreement to walk away after determining that required legal and regulatory approvals “were unlikely to be met” by dates specified in the deal, JetBlue said Monday in a statement. The company — which is also facing pressure from activist investor Carl Icahn to return to sustainable growth — will pay Spirit $69 million and the agreement resolves all outstanding matters related to the deal. “The probability of getting the green light to move forward with the merger anytime soon is extremely low,” JetBlue Chief Executive Officer Joanna Geraghty told employees in an internal message. “The lingering uncertainty is distracting and taking our resources away from more pressing priorities.” The decision ends JetBlue’s lengthy quest for Spirit and marks a sharp reversal after the companies pledged to fight for the tie-up — even as analysts said an appeal had little chance of succeeding. JetBlue had hoped to accelerate its growth with a quick infusion of Spirit’s planes and pilots at a time when both are in short supply.