Spanish airline Iberia and local Canary Island carrier Binter said on Friday they had cancelled some flights to La Palma due to the volcano erupting there.
"The evolution of the ash cloud in recent days ... has forced the airline to change its schedule, starting today, Friday 24 September, cancelling flights to the island at night," Binter said in a statement.
IAG unit Iberia also said on Twitter it had cancelled one flight on Friday afternoon because of the volcano.
Binter did not specify how many flights will be affected but said the rest of its operations continued as planned.
Since erupting on Sunday, the Cumbre Vieja volcano has spewed out thousands of tons of lava, destroyed hundreds of houses and forced the evacuation of thousands of people.
A cloud of toxic gas and ash extends more than 4 kilometres (2.5 miles) into the sky, the Canaries volcanology institute said on Thursday.
It has begun to drift northeast toward the Mediterranean and Spanish mainland, the AEMET national weather agency said.
Airspace above the island remains open apart from two small areas near the eruption site.