The question the Easyjet board should be asking itself is why US investment outfit Castlelake is in such a hurry to snap up the budget carrier.

The answer is the financial performance has been turbulent, but the sum of the parts of the group looks attractive to buyout barons.

Airlines are not just about branding, culture and reliability, which Easyjet has in spades. Unseen to everyone queuing and struggling with luggage at London's Gatwick is its dominance of slots at the airport. 

The right to fly at a highly valued time is a critical asset for most airlines.

British Airways has managed to vacuum up all the best North Atlantic slots at Heathrow through a series of smart takeovers. 

It is one of the main reasons that successive BA bosses have been lukewarm about a third runway.

It is not just the higher user fees that are a worry. What is really feared is that more flight capacity will allow US airlines, Virgin Atlantic and other rivals to grab market share on routes where business travel prices are crazy.

Castlelake is no stranger to the skies. In 2023 it led a consortium that rescued Scandinavian carrier SAS. It was no longterm proposition. It speedily flipped the carrier to minority partner Air FranceKLM after extracting value.

Broker Bernstein argues that Castlelake is more interested in exploiting trapped value - in the shape of aircraft leasing deals and slots - than in serving travellers.

Buying Easyjet would give Castlelake immediate access to the owned fleet of 200 Airbus short-haul aircraft as well as some 290 planes shrewdly on order over the next eight years.

Easyjet's biggest shareholder Stelios Haji-Ioannou has in the past been a critic of the carrier's forward buying of new aircraft. 

At a time when Airbus has a vast backlog of 9,000 orders for short-haul aircraft, Easyjet's queue position is a considerable, intangible asset.

The latest £4.9bn offer for the group is unlikely to be the last.

Shareholders should be fearful that chairman Stephen Hester is ready to wave the white flag, but there is resistance from other non-executives.

Hester has a history of selling valuable UK assets, as former shareholders in Royal Sun Alliance (RSA) could testify. 

Most private equity deals for UK firms are stacked in favour of the predator. Boards know that they are required to put on a show of defiance.

But as the bid price rises, they come under increasing pressure from investment bank advisers. If they allow the bird in the hand to fly away, they could be in breach of their fiduciary duty.

It should never be forgotten that for executives, a bid is a shortcut to riches. Most share incentive deals specify that in the case of a takeover, share options bought at a big discount or provided free are paid in full.

When Britain loses listed firms to private equity ghouls, it is not just the share quote which vanishes. Headquarters teams are ripped out, tax revenues for the Exchequer are savaged and pension funds discarded.

In Easyjet's case, a popular no-frills airline which has brought the magic of continental destinations to millions is at existential risk.