New American arms already delivered or promised to Arab nations and Israel have so much range that another Mideast war could be fought far beyond the borders of past conflicts.

The lengthening reach of American arms is most dramatic in the case of aircraft. Israel, thanks to aerial refueling, now has countries as distant as Libya and Saudi Arabia under the gun.

Saudi Arabia, if it receives the F15 fighters President Carter wants to provide, could fight in Israeli air space and have enough fuel left over to return home.

In short, the U.S. policy of arming both sides in the Mideast with increasingly lethal weapons has widened the potential area of conflict by thousands of miles.

Using Navy and Air Force estimates of combat radius for U.S. planes sent to Israel, here is how the strike distances have increased:

A4 Skyhawk.Ordered by Israel in 1966, asa the first American-supplied jet, the Navy Skyhawk with a typical load of bombs and rockets has a combat radius of 250 and 350 miles.

F4E Phantom. Armed primarily for bombing but carrying some air-to-air rockets and extra fuel tanks, the Air Force credits this fighter-bomber with a combat radius of about 440 miles.

F15 Eagle. Intended for dogfighting rather than for bombing in the attack role, the F15 is credited by the Air Force, when carrying extra fuel, with a radius of 900 miles.

F16. Although Israel already has received about 10 of the 25 F15s it has ordered, the F16 has not yet been bought. Israel is expected to buy about 150 F16s for both dogfighting and bombing.

The Air Force will only state that the F16 has a combat radius of over 500 miles. Inofficial sources credit the plane with ranges between 600 and 800 miles, depending on whether it is flying a dogfight or attack mission.

Unlike Israel, Egypt has yet to receive its first jet warplane from the United States. But Egyptian President Anwar Sadat hopes to recieve F5E fighter-bomber planes. The Air Force credits that plane with a combat radius of 250 miles for bombing and 300 miles for dogfighting.

Israeli leaders have strongly protested the proposed sale of F15 fighters to Saudi Arabia and warned against arming Egypt with American weapons.

The American Israel Public Affairs Committee is trying to mobilize public opinion against selling F15s to Saudi Arabia, declaring in a widely circulated memo that the planes "would enable Saudi Arabia to strike deep into Israel."

Saudi F15s, the committee asserted, "could neutralize Israel's F15s on a 1-to-1 basis and pose an unprecedented threat to Israeli bases and cities. . . The F15 can carry up to 12,000 pounds of external air-to-ground ordinance. . ."

The same F15 flown by Israelis poses similar military threats to Saudi Arabia and Libya.Israeli leaders have stated that no Arab country participating directly or indirectly in a war against Israel will be safe from retribution.

As much as the range of U.S. aircraft going to the Mideast has increased since the Six-Day War of 1967, many U.S. air war specialist believe the real advance is the Israeli aerial tanker fleet. One tanker can refuel several aircraft in flight several times, enabling fighter bombers to stay aloft longer and hit distant targets.

Although the Israelis already have an aerial tanker fleet, they want to modernize it by buying six USAF KC135 jet tankers, according to administration sources.

Just one KC135 tanker carries 31,200 gallons of airplane fuel, or 202,800 pounds. The tanker itself burns 2,415 gallons an hour while flying about 500 miles an hour.

One F4E Phantom fighter-bomber, including extra tanks, carries 3,195 gallons of fuel when flying a long-distance bombing run about 440 miles from its base.

After allowing for what the KC135 tanker itself would burn while flying 1,000 miles from Tel Aviv and back, about 10,000 gallons, that one tanker would have enough fuel to refill the tanks of six F4E fighters.

This would mean the fighters could fly twice as far, or almost 1,000 miles from the home field and return. Or, the F4E could substitute weapons for fuel before takeoff, receiving fuel aloft.

Tankers give an air force extra range, more punch and more time aloft for patroling or dogfighting. The United States purposely did not teach the South Vietnamese pilots aerial refueling, [WORD ILLEGIBLE] supply the tankers, for fear the South Vietnamese would bomb the farthest reaches of North Vietnam.

The Israeli air force, because of its tanker fleet, has no such leash. None of Israel's most likely opponents in a Mideast war - Egypt, Syria, Jordon, Saudi Arabia, Libya - has an aerial tanker fleet.