WASHINGTON, Nov 4 (Reuters) - A retired top U.S. Air Force general on Monday said South Korea will need Boeing Co F-15 fighter jets in the short term since Lockheed Martin Corp's F-35 will not be able to carry a full load of weapons until after South Korea needs to replace its aging F-4 and F-5 fighters.

Ron Fogleman, who works as a consultant to Boeing and also heads the board of Alliant Techsystems Inc, a big F-35 supplier, said South Korea would eventually need some F-35s, with their greater "stealth" or ability to evade enemy radar.

But Boeing's F-15 offered South Korea the ability to carry more weapons than the F-35 when it starts to retire its current F-4 and F-5 fighters in 2016 and 2017, given delays in the development of the F-35 software.

"You can buy a stealthy airplane, but if it doesn't have a lot of combat capability you kind of have a paper tiger," Fogleman told reporters.

South Korea is now reexamining its requirements for a $7.2 billion fighter competition, after an acquisition task force last month rejected a bid to buy the Boeing F-15 because the country needed more stealth capability.

Seoul is expected to reaffirm in coming weeks that it needs radar-evading capabilities like those offered by the F-35, according to sources familiar with the process.

However, Boeing and its supporters are pressing for a split buy of both F-15s and F-35s.

Fogleman, Air Force chief of staff from 1994 to 1997 and who headed the combined U.S.-Korean air forces from 1990 to 1992, said the F-35 would not be able to carry its full range of weapons until the 2020s after Lockheed completes work on the final 3F software being developed for the plane.

Lockheed did not immediately comment on the timeline for the software but has previously said it is working to complete the software as quickly as possible.

Pentagon acquisition chief Frank Kendall last week said the F-35 program was making progress, but he remained concerned about development of the plane's software, particularly the final 3F version, which he said was "behind schedule."

The early 2B software will allow the F-35 to carry two AIM-120 air-to-air missiles and two 1,000-pound satellite-guided bombs, or Joint Direct Attack Munitions, according to the Pentagon's F-35 program office.

The Navy says it will wait until late 2018 or early 2019, when the 3F software is done and the plane has its full combat capability, including the ability to carry a 2,000-pound JDAM, a stand-off weapon, and external weapons.

Fogleman, who says he has "a foot in two camps" on the South Korean competition, said the Navy's decision underscored that the F-35 would not reach its full combat capability until well after 2017, when South Korea says it needs new fighter jets.

Backers of the F-35 argue that even the early software will give military users more electronic warfare and other capabilities than any other fighter available today, in addition to being nearly invisible to enemy radar.