BySuzanne Rowan Kelleher,

Forbes Staff.

High-earning Americans are spending less on holiday travel this year, according to several recent industry reports—signaling a potential early threat to airlines that have come to rely disproportionately on luxury travelers.

Major airlines have come to increasingly rely on strong demand for their lucrative premium-class tickets—but multiple indicators show high-income Americans are pulling back on travel spending.

Comparing spending that occurred mainly in October versus September, “year-over-year airline bookings growth improved for every income group except the $150,000-and-up cohort,” Michael Gunther, vice president and head of insights at Consumer Edge, a provider of consumer spending data, told Forbes in an email.