Speaking in Brussels, Broughton said: "Finally, it has been a disappointment. The US administration has gone as far as it can go, but it is tinkering at the edges in terms of legislative action."
"We are looking for a barrier-free transatlantic market," he added.
On Nov 20, EU and US negotiators agreed to allow unrestricted competition on transatlantic airline routes, opening the prospect of cheaper tickets and more choice for passengers.
The agreement came after a week of talks at the US State Department, and was the latest round in a two-year drive to forge an "open skies" aviation deal between the US and EU.
But the EU made it clear that the US government will have to give more ground before a full and comprehensive accord can finally be signed, perhaps next year.
EU concerns focus on US legislation that continues to protect US carriers from foreign ownership.
The US Department of Transportation earlier this month proposed relaxing their rules to allow foreign investors a greater say in the operations of US airlines, but made no offer to change the 25 pct ceiling on voting rights.
Broughton is meeting with other EU and US company executives ahead of an informal EU-US economic ministerial summit tomorrow hosted by the UK presidency.