Pilot incapacitated, a crash landing and a close call. What we know about the latest aviation incidents

A series of aviation incidents is being investigated as the busy summer travel season begins, raising concern for passengers despite the differences among the events. CNN reports that a pilot medical emergency prompted an Air Canada diversion into Boston, while additional cases include a crash landing by a small plane in Alaska and a near-collision involving passenger jets over Boston. The Transportation Security Administration expects to screen nearly 18.7 million travelers at U.S. airport security checkpoints between June 30 and July 6 for the Fourth of July weekend. These developments come weeks after four plane crashes occurred in the U.S. within four days, killing 21 people, with no connection reported between the crashes. Ed Pierson, executive director of the Foundation for Aviation Safety, said investigations should focus on understanding causes and implementing fixes to prevent recurrence.