Bristol International Airport is 100% owned by South West Airports Limited (SWAL), a joint venture holding company owned by Bristol Airport (Bermuda) Limited (BABL) and Macquarie European Infrastructure Fund (MEIF). Both BABL and MEIF are managed by Macquarie Capital Funds (Europe) Limited (MCFEL), a subsidiary of Macquarie Group Limited.
MacBank are legendary for their labyrinthine accounting, to the extent where probably only MacBank knows what MacBank owns.
Some of their businesses are getting really walloped in the credit crunch. Broadly speaking, their businesses are massively leveraged, which is like taking out a massive mortgage against the value of the airport, probably to go and buy another airport. That's all fine and dandy whilst the revenue from the airport can keep up with the interest payments, and the airport value remains above that of the original price.
That's usually why MacBank businesses are so obsessed with cashflow - which is why they don't mind big building projects, but hate putting staff into operations, or cleaning things and so on.
I would guess that Bristol is still throwing off lots of cash - it's got relatively big passenger volumes, for a relatively small infrastructure cost. I'm guessing the cashflow from the airport is worth more than trying to get a lump-sum by selling it (particularly as it appears to be a buyers market for airports at the moment).
So my take is that MacBank will hold onto Bristol, as long as Easyjet and Ryanair and Charters keep the terminal packed to the gunwhales.