F-22 Stealth Fighter Jets Are Back In The Skies

America's F-22 fighter jets have returned to the skies, almost four months after being grounded over pilot complaints about a lack of oxygen. The F-22 is a stealth fighter aircraft that suffered from complaints at six different bases across the country. Instructor pilots were concerned over hypoxia issues that affected at least 12 pilots in the past three years.Hypoxia is when the body does not receive enough oxygen. The F-22's are now back in service.