Libyan sailors on warships off that nation's coast are seasick and Libyan pilots ordered to fly at night are afraid of getting lost in the dark, Pentagon officials receiving intelligence reports said yesterday.

Libyan leader Muammar Qaddafi sent his ships out to sea for fear they would be bombed in port by U.S. forces.

Defense Department officials said some of the ships are breaking down on the Mediterranean and others are low on fuel. As they roll in the chop, their crews are becoming ill.

The officials also said Libyan pilots ordered to keep their planes aloft at night to escape surprise attack are so afraid of getting lost that they are circling over lighted airfields.

Officials passing on this information with little attempt to disguise their glee apparently are receiving day-to-day reports on Libyan forces through the vast intelligence net spread over the region, including electronic eavesdropping equipment operated by the National Security Agency.

President Reagan has linked Libya to last month's terrorist attacks at the Rome and Vienna airports in which 19 persons were killed, and has refused to rule out some sort of retaliation if Libya were linked to another terrorist act.

The U.S. aircraft carrier Coral Sea, which the Joint Chiefs of Staff considered for use in action against Libya if Reagan had ordered retaliation, was outside the region yesterday, conducting exercises off Nice, France. One F/A18 jet from the carrier was lost during maneuvers yesterday and its Marine pilot killed, the Navy said.

Libya's largely coastal navy is not accustomed to staying out at sea for several days and nights at a time, and Qaddafi, sources said, has rejected his skippers' pleas for permission to return to port.

The naval officers have been reporting engine breakdowns, electronic failures and radars that will not operate, U.S. officials said.

The fleet is also running low on water, food and fuel, officials said, and it is not skilled in keeping ships resupplied during extended sea duty. To save fuel, many of the Libyan ships are lying dead in the water, officials said, which often causes a vessel to rock more, increasing the chances of seasickness.

On top of that, officials said, several storms have kicked up the Mediterranean over the last several days, making life even more uncomfortable for sailors on vessels designed for short coastal patrols.

The Libyan navy includes one frigate; nine corvettes, which are like mini-destroyers, and 30 patrol craft.

Libyan air force pilots have their own problems, the sources said, following Qaddafi's decision to disperse planes around the country.

Few Arab air forces -- including Syria's, which is much more sophisticated than Libya's -- operate at night because of the obvious dangers. Since U.S. bombers can strike in the dark, Libyan pilots have been ordered to keep planes aloft, giving them nerve-racking duty, U.S. officials said. The pilots are apparently afraid of getting lost or of having trouble coping with an in-flight emergency, the officials said, and are sticking close to lighted landing fields.

The Libyan air force, which officials say is no match for that of the United States or Israel, includes seven Soviet Blinder bombers and a mix of French and Soviet fighter planes. In addition, Soviet-made SA5 antiaircraft missiles are being deployed this month.

Libya is short of trained pilots, and U.S. officials said Libya often has used pilots of friendly nations to fly its warplanes.

According to Pentagon officials, another big weakness of the Libyan air force is its inability to find and identify aircraft. The United States, officials said, has often intercepted radio commands to Libyan pilots, telling them to close on an unidentified plane. A frequent reply, sources said, is: "I can't find him."