The FTSE 100 index was down 47.27 points, or 0.68%, at 6,893.32. Shares in Easyjet dropped 2.5% and British Airways owner IAG fell 2.1%.
The falls came as the price of oil hit five-week highs, with Brent crude hitting $48.74 a barrel.
Mining shares enjoyed a better day, helped by well-received results from Antofagasta.
Antofagasta shares rose 8.6% after it reported a rise in half-year core profits, and BHP Billiton climbed 0.7% despite it reporting a record annual loss of $6.4bn.
On the currency markets, the pound was given a slight boost after the UK inflation rate rose to 0.6% in  July, which was slightly higher than expected.
Sterling rose 1.13% against the dollar to $1.3025, and was 0.18% up against the euro at â‚¬1.1545.
(Close): London's benchmark share index closed lower, with shares in airlines amongst the biggest fallers.