Why do the cockpit windows open on some aircraft?

You might be surprised to see large passenger airliners with cockpit windows that open. Here's why some cockpit windows open, ...
kcra.com

Delta Air Lines pilots abort takeoff after window opens in the jet’s cockpit

A Delta Air Lines plane aborted its takeoff Wednesday morning after a window came open in the cockpit.Delta Flight 2261, a Boeing 737 scheduled to fly from Minneapolis to Las Vegas, was rolling down ...
CNN

Pilots abort takeoff after window opens in the jet’s cockpit

A Delta Air Lines plane aborted its takeoff Wednesday morning after a window came open in the cockpit. Delta Flight 2261, a Boeing 737 scheduled to fly from Minneapolis to Las Vegas, was rolling down ...