I realize that crapping on the F-35 is a cottage industry, but:
1. Failing to remove an air intake cover is a human error. Some plane handler or mechanic screwed up. It is not a design defect or a defective part.
2. Air intake covers are a normal part of storing and maintaining military jet aircraft. For example, this on an F-16:
The pilot is obligated to perform a walk-around of the aircraft prior to accepting it. Sounds like there's plenty of blame to go around.
Had an aircraft abort a mission at end of runway due to its configuration.
Test Engineers were using the correct flight clearance form, but no one, including the pilot, bothered to check and notice a 2000lbs. class bomb in the weapons bay that wasn't annotated on the form.