This post is in partnership with Time. The article below was originally published at Time.com.
By Justin Worland, TIME
The five biggest U.S. airlines all increased their base fare on domestic flights in the past week, despite declining fuel prices and apprehension over the potential spread of Ebola.
JetBlue (JBLU) initiated a $4 fare increase last Thursday, and United (UAL), Delta (DAL), American (AAL) and Southwest (LUV) followed suit, the Associated Press reports.
Though the airlines are trying to boost revenue with an across-the-board price increase, the effect it will have on the average consumer is less clear. Even with a base fare increase, airlines change prices frequently to adjust for evolving demand.
The move comes despite a slip in fuel prices (one of an airline’s largest expenses) and worldwide fear over Ebola. Both factors might seem to give airlines reasons to cut fares.
Wall Street seemed to reward the price increase with shares in the major airlines all gaining by at least 3%.