The F-35 Lightning II will fly with three different branches of the military in the U.S. and while the Marines have previously stated that it would field the F-35 with interim Block 2B software, the Navy and USAF have noted that they will not consider the jet formally operational until software Block 3B in the past. However, the USAF and Navy are now going back on that statement.

According to testimony given by leaders of the USAF and Navy before Congress, the F-35 could be considered operational and put into service with the Block 2B software in all branches if needed. That would be assuming that there were no safety concerns with the aircraft and that software.

Air Force Lt. Gen. Herbert Carlisle said, "If the combatant commander said, 'bring me this capability,' then we clearly would provide it."

Along with Carlisle, Navy Rear Adm. David Philman said, "I don't see any reason we wouldn't be able to be told to go into theater, assuming all the safety considerations have been taken care of."

The Navy and USAF will both have a number of F-35 fighters before the fleet is declared fir for Initial Operational Capability or IOC. Carlisle said, "We will have a number, probably on the order of a 100, airplanes delivered to operational units before we declare Initial Operational Capability. Clearly, although we may not declare IOC, we'll be training; we'll be doing the tactics, training and procedures with the Block 2."

Marine Lt. Gen. Terry Robling told congress that his service would declare IOC with interim block 2B software and that at least 50 F-35 fighters would be available near that time. Robling noted that IOC for the Marines was estimated to be in the 2014 to 2015 range. The F-35 is said to be vastly more capable than existing aircraft even with Block 2B software.

Carlisle said, "There is a lot of capability even in the Block 2 airplanes that look very impressive."

While the F-35 is moving along and may see service sooner than expected in some branches of the military, the U.S. is said to be losing its stealth technology lead. Military officials told Congress on May 24 that the lead in stealth tech held by the U.S. is eroding faster than anticipated.

General Carlisle told Congress, "Over time I believe we will still maintain an advantage, but I think our advantage will be a shorter period of time."

Carlisle cited aircraft like the Chinese J-20 fighter and the Sukhoi T-50 PAK-FA being developed in Russia as some of the aircraft eroding our stealth lead in America. America has held the stealth tech lead since 1970 with Carlisle noting the F-117 and said, "I don't see us maintaining an advantage for as long, as I think other nations will continue to gain that technology."