They had been led to believe last night that the flight was over and gloom had settled over the Navy base. Military men and Cuban employees here, a majority of whom favor the insurgents' cause, had heard stories that anti-Castro fighters had all but lost their battle.

Reports of a landing led by Nino Diaz in northern Cuba reached the base about midnight through a broadcast by an anti-Castro station.

Nino Diaz is a popular hero of some standing on the island for his previous participation in fights against dictatorships. He could be expected to rally some popular support if his unit gains a foothold in this area.

Yesterday the number of Cuban patrols outside the seventeen-mile fence surrounding this base were increased, but there was no unusually large build-up of Castro troops close to the base.

Rear Admiral Edward J. O'Donnell, commander of the base, reported that navy ships and planes had not been molested in their operations outside the base.

He said the United States under its treaty for the base with Cuba, enjoyed "de facto sovereignty" over this installation and therefore felt free to ignore the Castro Government's order forbidding foreign planes in Cuban territory.

Jet planes are on the alert here. Sailors or marines are patrolling the vital installation.

The admiral said he had no knowledge of a United States aircraft carrier in the area, as has been charged by Cuba. However, he announced that the carrier Randolph had left Norfolk, Va., after an overhaul and would arrive here for "routine training" Saturday.