U.S. cruise operators and travel agents said travelers have booked heavily for next year.

Even more than before the global health crisis.

Cruises are in demand as they are widely seen to be cheaper than land-based alternatives.

And with such popularity, operators plan to hike prices in the coming months.

One CEO described the market as 'extremely strong'.

And picked out the high-end luxury part of the sector as doing a roaring trade.

One industry watcher said bookings made in November for next year were about a fifth higher than in the same period in 2019.

Royal Caribbean Group CEO Jason Liberty also said recently that demand was outpacing 2019 levels by a wide margin.

Trade body Cruise Lines International Association said about 35.7 million passengers are expected to set sail next year - up from 31.5 million in 2023.

The figure is about 6% more than in 2019.

But there is one big catch for cruise lines as demand soars.

Bookings could be held back due to a lack of capacity.

Carnival CEO Josh Weinstein said earlier this year volumes for next year will fall back as the company could run out of inventory to sell.

Smaller operators also say volumes are overflowing.