Muhammad Ali Jr. was detained and questioned at a Washington airport before being allowed to board a flight to Fort Lauderdale after meeting with lawmakers to discuss a separate airport detention incident last month, a lawyer for the late heavyweight champion’s son said Friday. Ali and his mother, Khalilah Camacho Ali, were stopped at the Fort Lauderdale-Hollywood International Airport after returning from Jamaica on Feb. 7. They traveled to Washington on Wednesday without incident to speak to members of a congressional subcommittee on border security about that experience.