Trying to disrupt a trip abroad by Prime Minister Benjamin Netanyahu, whose hard-right government is seeking the changes, as well as a visit by Pentagon chief Lloyd Austin.
Protesters defied a heavy police deployment.
Travelers were forced to get out and walk with their luggage.
Protesters had called for "A Day of Resistance." They fear the reforms would subordinate Israel's Supreme Court to the executive and foster corruption.
The proposals have hit the shekel and alarmed Israel's Western allies about the state of its democracy.
Nationwide protests have erupted weekly since January.
"The government is trying to change the system here so that the government can enact any laws that it wants, without any restrictions, and moreover they want to have the power to appoint which ever judges they want. It is well known that absolute power corrupts absolutely."
Austin, who is on a regional tour, planned to relay U.S. concern about escalating tensions in the occupied West Bank.
Hours earlier, Israeli forces killed three Islamic Jihad gunmen there.
Austin's visit was hastily rescheduled because of the judicial-reform protests and his meetings relocated close to the airport.
Netanyahu - who is on trial on graft charges he denies - argues that curbing the judiciary would restore the balance between the branches of government.
Polls have found most Israelis want the plan to be shelved or amended.
