As Israeli jets flew over Beirut and southern Lebanon and military maneuvers were reported in Syria, the United States was said to be considering widening political contacts here to help defuse the Middle East missile crisis.

U.S. envoy Philip Habib is due to arrive here Thursday on the first leg of a shuttle Washington hopes will result in Syrian withdrawal of missiles in Lebanon's Bekaa Valley before Israel tries to take them out by force. Although Habib has scheduled meetings only with Lebanese government offiicals before his departure Friday for Damascus, other Lebanese leaders representing various feuding factions were preparing to see him.

Reports from diplomats and other analysts here indicated that Haibib may confer with political factions outside the government, the most important of which is the Phalange Party, the core of the Christian militias battling Syrian peacekeeping forces here.

The Phalangists, whose good will would be required to bring any long-term negotiated end to the domestic hostilities that provoked the larger missile crisis, have made no secret of their delight with the Habib mission, which they consider a breakthrough with a government they feel has consistently opposed them since the Lebanese civil war erupted in 1975.

Diplomats noted that although U.S. moves technically are limited to resolving the missile crisis, the internal dynamics of the problem have suited militia goals. Such official U.S. consecration for a party that was once almost a pariah would remain even if the Habib mission fails, according to the diplomats and other informed analysts here.

Meanwhile, Soviet First Deputy Foreign Minister Georgi Korniyenko arrived in Damascus for a three-day visit.Korniyenko said he planned to "discuss various issues of mutual interest" with Syrian President Hafez Assad, whose government signed a defense and cooperation agreement with Moscow last October.

Local politicians and diplomats suggested that the United States, working through Habib, would try to bring about face-saving changes on the ground in Lebanon which could buy time and create the impression of movement acceptable to all parties.

These sources argued that a package deal giving points to the Syrians on some questions, and to the Israeli-backed Christian militias on others, would create an atmosphere in which the Syrian missiles either could be withdrawn or glossed over.

Potential points of agreement of solving the current round of Christian-Syrian hostilities had been worked out, at least on paper, before Israel last week shot down two Syrian helicopters and Syria replied by installing the SA2 and SA6 ground-to-air missiles.

For example, diplomats noted, Israeli Prime Minister Menachem Begin has demanded the removal of the missiles and the Syrian troops from the Lebanese mountain ridges surrounding the Christian Bekaa Valley city of Zahle. Informed sources said that the Syrians themselves have left the ridges, which are now in the hands of their Lebanese allies and could be handed over to the Lebanese Army without major argument.