A light rain fell at the Zurich airport one Sunday morning in January 2023 as Sarah Kate Ellis made her way from a seat in Delta’s most exclusive cabin to a waiting Mercedes. It was there to chauffeur her to the Swiss Alps, where she and her colleagues would stay at the Tivoli Lodge, a seven-bedroom chalet that cost nearly half a million dollars to rent for the week.

Ms. Ellis, who was en route to the World Economic Forum in Davos, doesn’t run a Wall Street bank or a high-flying tech start-up. She is the chief executive of the nonprofit organization GLAAD, one of the country’s leading L.G.B.T.Q. advocacy groups.

The group, which has an annual budget of roughly $30 million, paid for Ms. Ellis’s trip, as well as a day of skiing, according to internal documents reviewed by The New York Times and interviews with current and former employees and others with knowledge of GLAAD’s operations.

The trip was part of a pattern of lavish spending at GLAAD, much of it by Ms. Ellis, that may have violated the organization’s own policies as well as Internal Revenue Service rules.

The Times reviewed dozens of GLAAD expense reports and accompanying receipts from January 2022 through June 2023, as well as employment agreements, tax filings, audit reports, other financial documents and internal communications.

When Ms. Ellis traveled for work, there were first-class flights, stays at the Waldorf Astoria and other luxury hotels and expensive car services. Not to mention a Cape Cod summer rental and nearly $20,000 to remodel her home office, which was outfitted with a chandelier, among other accouterments.