Airbus always had an unfair advantage over Boeing because of the overt and covert subsidies it receives from the European nations that own interest in it. Although Airbus tries to make a case that Boeing is also subsidized by the US government to some degree (if they want to count sales of military products), it would be very naive to think that Airbus is not able to undercut Boeing on price and financing because of its government underwriting.

Although it would violate at least the spirit of the existing trade treaties to coerce US carriers, directly or indirectly, to focus their purchases on Boeing exclusively (and offer tax breaks to offset the price difference), I think the best arsenal against Airbus and the 380 are the airports themselves.

No one can say "don't buy this aircraft" without touching off a trade war, but the major US hub airports like JFK, LAX, ORD, MIA, etc. can simply state "we are not upgrading our facilities to service this aircraft, and no landing permits will be issued for this aircraft unless flying cargo only and taxiing to a cargo processing facility". In one shot, you have made the purchasing decision alot more difficult for those international (and possibly domestic) carriers considering an order - and these airports are so busy with capacity demand outstripping supply, it's unlikely any carrier like BA or SQ will storm off and cut service to vital markets like these.

The FAA does not have the authority to require airports to service (outside of emergencies) any particular aircraft type, so the federal gov. can just take a hands-off approach and say 'it's not up to us' if the European Union complains about a covert tariff.

I find Airbus' analysis of the global passenger aviation market to be flawed - their guesstimate that passengers and airlines are best served by a cookiecutter solution of A380s sending huge numbers of passengers between major global hubs to be sent off to A320s and 319s for distribution to secondary and tertiary markets is not the direction most airlines or passengers want to go. The Boeing model of flexible, comfortable, mixed-range aircraft based on the 777 and 787, with secondary distribution to 737s and a focus on point-to-point service between markets with ideal O+D traffic loads is the better option. I will concede that the 380 would make a good all-cargo or mixed-cargo/pax plane.