A 24-hour strike will impact flights using Portuguese airspace tomorrow.
Ryanair has been forced to cancel over 60 flights while TAP Portugal is advising customers to re-book for alternative dates.
Passengers can rebook, once, free of charge as long as one of the segments of their flight is impacted.
New flights must be either two days before or after Wednesday (November 24).
British Airways says it will cancel its three return flights into Lisbon.
A spokesman for the carrier said: "Naturally we apologise to all our customers for this inconvenience but this is beyond our control."
Strikes in Belgiam, France and Spain have already impacted airlines this year.
Ryanair said it has been forced to cancel over 2,000 flights and delay over 12,000 other flights as a direct result of strike action in 2010.
