Revenge Travel Runs Out of Force, Hurting Airlines’ Profit Goals

Just as the annual summer vacation gets underway in Europe, airlines in the region are feeling a cold chill wafting over the Atlantic from their US counterparts.

On Wednesday, United Airlines Holdings Inc. became the latest carrier cautioning weakening profitability, joining the likes of Alaska Airlines Group Inc. and Delta Air Lines in offering a muted outlook. Airlines have warned of falling ticket prices amid a fare war that’s weighing on their profit, hurting carriers during a time of the year that normally marks an industry peak.

Some of that pessimism on display in the US has already taken hold ...