Major General James Post was removed from his position as the vice commander of Air Combat Command and received a letter of reprimand, the air force said in a statement.
The two-star general sparked an uproar over his comments in January to a group of airmen at Nellis Air Force Base in Nevada, when he addressed the long-running debate about air force plans to scrap the A-10 aircraft.
"If anyone accuses me of saying this, I will deny it... anyone who is passing information to Congress about A-10 capabilities is committing treason," he reportedly told the airmen.
The decision to sack Post was taken by General Herbert Carlisle, head of Air Combat Command, after a report from the air force inspector general into the episode.
The inquiry found that Post's "choice words had the effect of attempting to prevent some members from lawfully communicating with Congress," which violated US law and Pentagon directives.
Lawmakers who have argued to keep the aging A-10 "Warthog" in the air had voiced outrage over Post's comments. The chairman of the House Armed Services Committee, Mac Thornberry, backed the decision to discipline Post.
"Members of Congress must be able to receive unfiltered facts and opinions from service members in order to fulfill our duties under the Constitution," said Thornberry.
"Attempts to prevent or restrict that communication cannot be allowed," the Republican said in a statement.
The US Air Force has repeatedly tried to retire the fleet of nearly 300 A-10 attack planes, arguing that the move would free up funds for new, more sophisticated aircraft such as the F-35 Joint Strike Fighter.
But lawmakers have pushed back against the proposal, saying the slow-flying "tank killer" - armed with a powerful 30mm Gatling gun - is ideally suited to protecting troops on the ground.
The A-10 planes have taken part in air strikes in the US-led campaign against the Islamic State group in Iraq and Syria.
In a statement, Post said he regretted his "impromptu remarks" and "I offer my humble apology for causing any undue strain on the command and its mission."