The strike by members of Unite, Britain's biggest trade union, grounded many BA flights at London's Heathrow Airport. Flights to and from Glasgow, Manchester, Amsterdam, Paris, Milan and Munich were among those most affected in a reduced timetable.
BA says it will attempt to maintain operations as much as possible.
"Our operations around the world have got off to a good start," BA said in a statement. "The numbers of cabin crew reporting at Heathrow are currently at the levels we need to operate our published schedule."
Although the atmosphere cleared when BA and Unite reached a broad agreement on pay, activity below the surface became increasingly heated as negotiatons turned to flight discounts for off-duty cabin crew, a key perk taken from the striking workers.
Discussions became blocked when dozens of Socialist Workers Party protestors wafted into the talks venue on Saturday.
Increasingly hostile discussions hit a low point on Monday, when Tony Woodley, the union's joint leader, accused BA CEO Willie Walsh of wanting "regime change" in the union's cabin crew branch.
Meanwhile, striking workers rallied near Heathrow.
"It's personal now," said one 42-year-old cabin crew member, speaking on the condition of anonymity.