F-35 operations will resume Wednesday at Luke Air Force Base in Glendale, according to U.S. Air Force officials.

The fighter jets were grounded for 11 days after pilots reported symptoms related to oxygen deprivation.

No one was hurt in the five incidents that started in May. Experts have not identified a specific root cause, but Air Force officials have outlined several ways to reduce risk going forward:

• Pre-flight procedures will change to help protect pilots.
• The F-35s will not fly at the altitudes where the incidents happened.
• The minimum of amount of backup oxygen required for each flight will go up.
• Pilots can choose to wear data-collecting sensors while in flight.
• Pilots will participate in additional training with medical experts.