Mardi Gras gives people the opportunity to celebrate before the Lenten season, where people become more disciplined and give up habits for 40 days.

The promise from authorities for more security threatened to conflict with the city’s anything-goes sensibilities, and some changes were evident.

A Delta Air Lines flight bound for New Orleans returned to Boston Logan International Airport on Sunday after a “smoky odor” was detected in the cabin, officials said. Flight DL1398, carrying 87 passengers, three flight attendants, and two pilots, declared an emergency shortly after takeoff to get priority handling from air traffic control.

A Delta Air Lines flight to New Orleans Sunday morning was forced to return to Boston after a “smoky odor” was detected in the aircraft’s cabin, the airline said.