A share price gain of only 10% on a possible takeover approach is a meek reaction. If the stock market truly believed that Castlelake, a US investment fund, stood a decent chance of buying easyJet, you would expect the target’s stock to fly significantly higher. Scepticism is the right stance until at least three factors become clearer.

First, would the two sides even be vaguely in the same landing zone on valuation? EasyJet’s description of Castlelake’s timing as “highly opportunistic” was boilerplate rhetoric (all bids are opportunistic to a degree) but in this case it is clearly possible that all European airlines’ prospects could be brighter within a couple of months.

It all depends on the price of jet fuel, which itself depends on resolution of the Iran war, and also how the peak summer season shapes up. The conflict has knocked consumers’ willingness to book ahead, but that does not mean they will not show up for overseas summer holidays if disruption is minimal.

City analysts still estimate that easyJet’s pre-tax outcome could be as low as £100m this year, which is virtually a washout against £665m a year ago. Yet the half-year numbers only a fortnight ago kept alive the “medium-term” target of more than £1bn “as conditions normalise”. If the chair, Sir Stephen Hester, really believes £1bn is possible in time (despite persistent underperformance versus Ryanair) it is hard to see how he could credibly enter takeover talks at anything other than a very fat premium to the starting share price of 400p. Only a year ago the shares were approaching 600p under sunnier skies.

An alternative metric is the value of the assets. As Goodbody’s analyst puts it, easyJet “is effectively a bundle of aircraft assets, orderbook assets and airport landing slot assets”. The broker puts the book value of the owned fleet at 615p a share; Bank of America thinks 650p. If Castlelake, mostly a lender to the airline industry rather than an owner, has spotted a way to exploit the discount to book value via, say, not taking delivery of some of the aircraft, the same technique is presumably available to easyJet in standalone form. You don’t have to sell the entire company in order to sell a few aircraft.

Second, how would Castlelake, as a US entity, get around European ownership restrictions? The rules say majority UK/EU ownership is required, so presumably the would-be bidder has some form of fancy footwork in mind. But what? A European partner? There would surely have to be clarity before any talks could start, otherwise what is the point? What easyJet calls the “deliverability” of any bid proposal is not a small consideration.

Third, what does Sir Stelios Haji-Ioannou think? The founder doesn’t lob as many insults at easyJet’s board these days, but he and his family still have a 15% stake, which is enough to throw a spanner in the engine if that is how he is minded.

None of which changes the fact that easyJet has been seen as a plausible takeover candidate for about a decade. The company is regarded as a loose piece in the pan-European jigsaw whenever aviation specialists plot ways in which the market could follow the US path of consolidation. It’s just that actual airlines, as opposed to financiers such as Castlelake, are seen as the most likely instigators. IAG, the owner of British Airways, is usually seen as the natural long-term destination for easyJet. Certainly, Hester and co would have to whip up some competitive tension if Castlelake can demonstrate how it would clear the regulatory hurdles.

The would-be bidder says it has bought a 2% stake in easyJet, which demonstrates some level of seriousness. But that’s about all Castlelake has said. The departure lounge for a bid still feels a way off.