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

A series of aviation incidents is unfolding as the summer travel season begins, highlighting how quickly flight safety can become a concern for passengers. CNN reports that a pilot medical emergency forced an Air Canada flight to divert in Boston, while other incidents under investigation include a small-plane crash landing 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. The events come weeks after four U.S. plane crashes in four days that resulted in 21 deaths, none of which were reported as related. Ed Pierson of the Foundation for Aviation Safety said investigators should determine what happened and how to prevent repeat incidents.