Too soon to gauge Brussels impact, but CCL is holding its guidance

'It's too early for us to know the impact,' Carnival president and ceo Arnold Donald said. Historically, such as after the Paris attacks, there was 'some impact on bookings' but that 'faded pretty quickly.'

So far, Carnival hasn't detected 'anything dramatic' as a result of Brussels.

'Right now, we see no reason to change guidance,' Donald said.

In fact, today Carnival lifted the midpoint of its full-year 2016 earnings guidance by a nickel per share on stronger bookings and pricing.

There have been some itinerary changes based on terrorist incidents. Particularly in the past year, lines have dropped Turkey, though a number of Carnival brands are still going there.

Carnival is continuously in touch with security experts and safety is the company's top priority, Donald said, but what's guiding these decisions is 'guests' desires to go to destinations.'