The two F-22 pilots who decided to speak out publicly about a mysterious, potentially deadly problem with America's most expensive fighter jet, the F-22 Raptor, are "fully protected" and others will not be reprimanded for asking not to fly the planes, a top Air Force official said today.

The Raptor, the U.S.'s only operational next-generation stealth fighter, has suffered at least 25 incidents since 2008 in which its pilots experienced "hypoxia-like symptoms" including dizziness, disorientation and nausea in mid-air. One pilot became so disoriented that his plane dropped down and skimmed treetops before he managed to pull up and save himself. Another pilot's plane suffered a catastrophic malfunction that shut off his oxygen system, leaving him to experience what the Air Force called a "sense similar to suffocation" in the minute before his fatal crash into the Alaskan wilderness during a November 2010 training mission, as reported in a recent ABC News "Nightline" investigation.

Over the weekend, two F-22 pilots spoke out to CBS News' "60 Minutes" about their concerns with flying the F-22 and claimed that the Air Force had sent a message to pilots that "if you speak up about safety, you're going to be out of the organization," as one of the pilots put it. Before the CBS report, a top Air Force official said that a "very small" number of F-22 airmen had asked not to fly the $420 million-a-pop planes, citing safety concerns.

Testifying before a Senate Armed Services subcommittee hearing, Air Force Lt. Gen. Janet Wolfenbarger said that the two pilots who spoke out, along with any pilots who express reservations about flying the planes, will not be reprimanded.

"There is clearly whistleblower protection," Wolfenbarger said. "They are fully protected."

The Military Whistleblower Protection Act allows for members of the armed forces to contact members of Congress, Inspectors General, law enforcement organizations and other regulating bodies concerning any number of potential legal or regulatory violations including threats to public safety. The two pilots who spoke to "60 Minutes" did so in the presence of Rep. Adam Kinzinger (R.-Ill.) in order to be afforded protection under the act.

Col. Thomas Wark, commander of the Virginia Air National Guard's 192 nd Fighter Wing under which the two pilots fly, told ABC News Monday the Guard would "not consider using disciplinary action as a means of reprisal."

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The Air Force has launched multiple investigations into finding the root cause of the mystery oxygen problem - including a nearly five-month fleet-wide grounding last year - but has so far come up blank. Wolfenbarger said today the Air Force believes there are two possibilities: either the pilots are breathing in toxins along with their oxygen, or they're simply not getting enough oxygen. The incidents are exceedingly rare, the Air Force said, 25 cases compared to thousands of missions flown without incident.

After a half decade since the first reported incidents, Wolfenbarger said the Air Force is "starting to believe we're coming close to closure" on the cause but did not provide any more details.

Still, the Air Force maintains that the planes are safe enough to fly and, following the "Nightline" and "60 Minutes" reports, the Air Force's Air Combat Command head Gen. Mike Hostage said he'll soon be jumping in the cockpit himself.

"I'm asking these guys to assume some risk that's over and above what everybody else is assuming, and I don't feel like it's right that I ask them to do it and then I'm not willing to do it myself - that's not fair," he said.