Author: John Cox, Special to USA TODAY

This week, Captain John Cox explains which tools pilots use to check to make sure they are flying level.

Retired airline captain John Cox answers your questions, from flying altitudes to the easiest airport to operatie in and out of in Washington, D.C.

Wear this to be safe

This week, Capt. John Cox tackles the issue of connecting through airports in states that require visitors from COVID-19 hotspots to quarantine.

This week, readers ask about the safety of flying first class nonstop and the use of ultraviolet light to sanitize airplane lavatories.

This week, retired pilot John Cox answers your question about HEPA filter maintenance and how they mitigate the chance of contracting COVID-19.

This week, retired pilot John Cox talks about what kind of damage turbulence can do to a plane and how co-pilots came to be called first officers.

Capt. John Cox explains why the process to recertify the Boeing 737 Max has taken over a year and why he’d be willing to take a leisure flight now.

This week, retired US Airways pilot John Cox tackles the deboarding process and what would happen if both pilots became incapacitated.

The number of passengers definitely can change the performance of any airplane. Before every takeoff, the pilots compute the weight and balance.