Travelers were told to arrive at the airport early because of the busy summer season.

A Transavia plane is seen in Orly, France.

The airline fixed the check-in issues by Sunday and is helping affected passengers find new flights.

Schiphol Airport expects over 12.7 million passengers in July and August, a bit more than last year. This shows people still want to travel in the summer. The airport was busy last year too.

Schiphol Airport is one of Europe's busiest airports, serving many passengers each year. But this summer, more people are traveling, which is causing congestion and longer waits.