United Airlines Holdings Inc (NASDAQ:UAL, XETRA:UAL1) shares rose about 6% on Wednesday after the carrier issued an upbeat summer travel forecast, pointing to strong demand driven by major global events, peak holiday travel, and continued momentum in international bookings.

The airline said it expects more than 53 million passengers to fly United between June and August, an increase of roughly 3 million from last summer.

United said it is seeing double-digit increases in bookings to destinations linked to these “once-in-a-lifetime moments,” including European cities in the path of the August 12 solar eclipse, such as Bilbao, Madrid, Barcelona, and Reykjavík. Astro-tourism demand alone is up more than 50% on select routes, according to the company.

The airline also reported a nearly 20% rise in bookings to North American host cities for international soccer matches scheduled between June 11 and June 27, including Mexico City, Toronto, and Los Angeles.

Meanwhile, travel to entertainment hubs such as Amsterdam and London is also trending higher ahead of major concert residencies and summer show schedules.

United is forecasting a particularly busy Memorial Day period, expecting around 3.9 million passengers between May 21 and May 27, or roughly 575,000 travelers per day across about 5,000 daily flights. That compares with about 270,000 fewer passengers over the same holiday stretch last year.

"Whether travelers are flying to witness a solar eclipse, cheer on their team or see their favorite artist live, our goal is to provide convenient flight options and a seamless travel experience, making it easy for them to get wherever they want go around the world," said Patrick Quayle, Senior Vice President, Global Network Planning and Alliances at United Airlines.