"We came at 4:30 am (0130 GMT) for our flight at 8:00 am but they told us it was cancelled," said Elham Shukair, a passenger headed to the United States via Jordan.
Seated on her bag in the arrivals hall, she said she had booked another flight later Sunday with Lebanon's Middle East Airlines in the hope of reaching Amman and making her onward connection.
Lebanon's Iran-backed Hezbollah movement has traded near-daily fire with Israeli forces in support of ally Hamas since the Palestinian militant group's October 7 attack on Israel triggered the Gaza war.
But Israel launched air strikes into Lebanon on Sunday, saying it had thwarted a large-scale Hezbollah attack, while the Lebanese group announced its own cross-border strikes to avenge the killing of a top commander, Fuad Shukr, in an Israeli strike last month.
Fears have spiked since Shukr's killing that the cross-border violence could degenerate into all-out conflict between Hezbollah and Israel, who last fought a devastating war in the summer of 2006.
Israel bombed Beirut airport, Lebanon's only international passenger facility, during that war.
On Sunday, other passengers sat on the floor in the arrivals hall as screens showed cancelled or delayed flights, while the arrivals area was largely empty.
"Our flight is still scheduled but it is delayed," said Diala Hatoum, who was set to travel with her son on a Qatar Airways flight.
"We will see, we are waiting now," she added.
Air France said it was suspending Beirut flights scheduled for Sunday and Monday, adding that the move could be extended depending on the situation in the Middle East.
Royal Jordanian Airlines announced the suspension of Beirut flights "due to the current situation", and the UAE's Etihad Airways said it had also cancelled its services to and from the Lebanese capital.
On Friday, German airline giant Lufthansa said it was extending a suspension of flights to Beirut until September 30.
Lebanon's civil aviation authority emphasised Sunday that "the airport is functioning normally" despite some disruptions.
There is "no truth" to rumours that all flights have been cancelled, said a statement from the authority carried by the official National News Agency.
A number of airlines had already announced flight suspensions or cancellations to Beirut in recent weeks, with some later resuming services.