JetBlue Airways (B6, New York JFK) has once again improved its offer to buy Spirit Airlines (NK, Fort Lauderdale International) in its latest effort to fend off rival Frontier Airlines (F9, Denver International), as the two would-be suitors fight to secure a fast track to expansion amid resurgent air travel demand across the United States despite labour and aircraft shortages.

Following Frontier Airlines Holdings’ initial proposal in February, JetBlue sought to outbid this offer and has sweetened its bid three times since. It has now raised it to USD33.50 per share, up from USD31.50 two weeks previously, in what it called “a decisively superior proposal” to acquire all of Spirit’s outstanding common stock, it outlined in a statement on June 20.

Spirit revealed last week that it was in talks with JetBlue about the terms of its proposal and could vote on any new proposal by June 30.

Besides the improved cash offer, the terms - which JetBlue said are “structured to maximise value and certainty for Spirit and its stockholders” - include commitments from previous proposals such as a reverse break-up fee of USD350 million and accelerated prepayment of USD1.50 per share.

The new proposal also includes a “stronger divestiture commitment” to sell certain assets of JetBlue and Spirit that would not adversely effect a combined JetBlue-Spirit but would affect its Northeast Alliance with American Airlines, JetBlue claimed. Spirit’s board had previously rejected the JetBlue offers because it feared antitrust regulators would reject them given the dominance of this existing alliance in the Boston and New York area.

“A combination between JetBlue and Spirit Airlines would create a true national competitor to the dominant legacy carriers, delivering low fares and a great experience for more customers, more opportunities for crew members and team members, and more value for stockholders,” CEO Robin Hayes urged. “While our strong preference is to reach a friendly, negotiated agreement with you, should the Spirit board fail to declare our improved proposal a superior proposal, we fully intend to continue our 'vote no' campaign against the Frontier transaction at your special meeting on June 30.”

Spirit said it would review the revised offer and stressed that it “continues to be bound by the terms of its merger agreement with Frontier, under which a 'superior proposal' is defined as being both reasonably capable of being consummated and more favourable to Spirit’s stockholders from a financial point of view.”

JetBlue also announced on June 20 that its low-cost flights to London - so far its only services to Europe - were being “enhanced” now it had secured permanent slots at London Heathrow and was adding a new London Gatwick departure from its New York JFK base. According to the ch-aviation capacities module, it currently operates both routes 7x weekly.

JetBlue has received permanent slots at Heathrow Terminal 2 for flights starting October 29, “which secures the airline’s long-term future” there. And, also from the same date, the carrier will operate a second daily frequency to Gatwick. The airline’s flights between the US and London are operated using its A321-200NX(LR)s.