Unfortunately, I wouldn't be so sure about approval by the European Transport Council; the UK Govt will be under severe pressure to veto it (see article in today's Independent); BA and VS want it like they want a hole in the head and they will be lobbying furiously to veto it. Unfortunately, they can do just that, because qualified majority voting does not apply.
The information I've been given is that since no change in US law is brought about by this, Congressional approval is not required. However, this could be a moot point.
It seems ridiculous that with 26 countries wanting a deal and one not wanting it, that one country could wreck it for everyone. The Americans may well have to threaten Britain with a revocation of Bermuda II, to put some pressure on.
If the UK does wreck it, then what next? Clearly if every other country wants the deal, why can't they go ahead. Why should BA have a veto over EI's ability to expand its t/a links? Surely, the best option would be for the US and UK to thrash out their differences, under EU supervision and everyone else should just go ahead with the deal as agreed.