By David Shepardson WASHINGTON (Reuters) -An American Airlines passenger who allegedly shoved a flight attendant and spit at crew members has been hit with the biggest fine ever issued by U.S. aviation regulators, and another fine topping $75,000 was issued to a Delta Air Lines passenger who bit a fellow passenger after trying to hug and kiss another. Since January 2021 when the Federal Aviation Administration (FAA) imposed a zero-tolerance policy, the agency has proposed fines of about $7 million for disruptive passengers. Two new fines issued Friday were the highest yet. The FAA proposed a $…