What design feature do aircraft hatches and windows commonly have?

Aircraft hatches and windows often utilize a plug type design because this configuration enhances safety and structural integrity during flight. In a plug type design, the hatch or window is molded to fit tightly within the aircraft’s frame, preventing it from being pushed outward during changes in cabin pressure. This is particularly crucial during takeoff and landing when pressure differentials can occur.

The plug type design helps ensure that the hatch or window remains secure even under high-stress conditions. Additionally, this design allows for the efficient transfer of loads without compromising the aircraft's structural stability.

The other design features mentioned do not offer the same level of security and effectiveness that the plug type design provides—removable designs might not maintain pressure integrity, sliding designs can introduce vulnerabilities in terms of leaks and gaps, and rotating designs are not practical for the operational needs of aircraft hatches and windows.