Airlines and cruise operators were among the steepest premarket decliners Monday as escalating conflict in the Middle East rattled investors and sent oil prices sharply higher, Barron’s reports.

Cruise lines led the downturn, falling roughly 6% to 7% in early trading. Major U.S. carriers also dropped more than 5%, putting travel shares under heavier pressure than the broader market.

While renewed missile strikes across the region could create limited itinerary changes and flight disruptions, analysts say the larger threat to the sector is rising fuel costs.

Crude prices climbed about 8% early Monday after the Strait of Hormuz — a critical global shipping route — was effectively shut down, fueling expectations of higher jet and marine fuel expenses.

For most U.S.-based airlines and cruise companies, direct exposure to the region remains relatively small.

Previous conflicts have shown that only a modest share of itineraries involve Middle East destinations. Some carriers have already suspended select routes and offered passengers flexibility to rebook through late March.

Still, if elevated oil prices persist, higher operating costs could weigh heavily on profits across the travel industry in the weeks ahead.