The fact that Coventry Airport is up for sale - or open to offers or whatever the official line is - should not be considered surprising.

The TUI tourism empire includes a handful of cruise liners, 400 hotels, 800 travel agents and 45 planes but just the one airport. Running air terminals is not its business.

However, the suggestion that it has been offered to Birmingham International Airport and BIA might be prepared to deal - at a more favourable price - is a different matter altogether.

Since TUI bought Coventry Airport in February 2004, BIA's disquiet grew steadily in private to the point where they went public with their misgivings through this newspaper.

Then it went beyond that to the current state of play, where BIA is to be the major objector at an forthcoming public inquiry into a permanent terminal at Baginton.

Now that Warwick District Council, the planning authority formally opposed to expansion at Coventry Airport, has entered into a conditional agreement with the airport management over compensation packages for affected residents, January's inquiry will to all intents and purposes be Coventry versus Birmingham.

The deal, if it ever happens, would presumably be a simple case of taking over the closest business rival.

BIA's concerns are twofold. Coventry operations could constrain airspace when and if BIA expands with an extension to the existing runway and then a new second runway.

Further, the existence of an established Coventry Airport, operating at around two million passengers a year by the end of the decade, seriously harms the business case needed to attract investors to build said second runway.

However, whether knocking out those concerns is worth buying a new airport which is not blessed with adequate infrastructure and dogged by bitter local opposition, is open to question.

The expansion of BIA - despite being approved by the Government's Aviation White Paper in December 2003 - was never going to be easy financially.

The expertly timed press conference (a couple of hours before Transport Secretary Alistair Darling announced the White Paper in the Commons) revealing passenger flights were soon to begin at the freight and private aircraft strip ten miles away in Baginton immediately made it harder again.

About half of the air passengers in the West Midlands disappear off to Manchester or London to catch their planes. That untapped demand is the prize on which BIA is basing its case for a second runway.

It was less than happy when TUI came along and stuck its own straw in that pool of passengers and began drinking. Not that the waters haven't been choppy for Coventry.

TUI was forced to step in when the previous owners of the airport, who had struck the deal for the launch of low cost airline Thomsonfly in the first place, began attempting to put in place runway turning circles and a car park without planning consent.

Warwick District Council were alerted and the touchpaper on an 18-month war between the two was lit.

The battlegrounds included the High Court and the WDC council chamber, where many dramatic planning committee meetings and the first planning inquiry into the legality of the temporary terminal were held.

However, apart from January's inquiry into the permanent terminal at Coventry, the worst seems to be over for TUI and this may be why it is now ready to sell.

Bill Savage, the managing director headhunted by TUI to run the airport, told The Birmingham Post last night that from the moment TUI bought the airport, expressions of interest were received.

"TUI took the line that the planning issues had to be dealt with responsibly first. But about half a dozen major airport operators have stayed the course.

"But now, as I say, I can see a light at the end of the tunnel on those planning issues, TUI would be silly not to consider selling the 142-year lease on the airport because airports are not part of their core business.

"One day, I am sure a partnership will be entered into or the lease will be sold to an operator. Whether that is now, at the end of the first planning inquiry, or next April at the end of the second, I don't know."

He was keen to stress that whatever happened TUI's commitment to Coventry was total.

"That is why there is a clause in the lease agreement that commits TUI to growing the Thomsonfly business at Coventry Airport. That clause would transfer if another operator bought it."

As to whether BIA was approached by Coventry Airport or vice versa, Mr Savage would only say: "That is like a playground tale of who kissed who first."

Having covered the Coventry Airport saga for nearly two years now, the idea of any of the major players puckering up for each other is strange.

But, the other thing you learn is to expect the unexpected: in fact, you could bet your airport on that.