Sir Stelios Haji-Ioannou, the founder of Easyjet, has resigned from the airline's board, saying he is unhappy with the way the company operates.
Sir Stelios said in a statement: "For some time I have firmly believed that the Easyjet management was pursuing the wrong strategy for... expansion."
The budget airline is aiming to expand its share of Europe's short-haul market from about 7% currently to 10%.
Sir Stelios plans to lead a revolt against the plan.
Easyjet said in a statement: "The stated reason for the resignation is that Sir Stelios... wishes to gain greater freedom to exercise Easygroup's rights as a shareholder in the company to seek a change in the company's strategy."
Easygroup owns a 26% stake in Easyjet.
Sir Stelios and another director, Bob Rothenberg, who has also resigned, represented the holding company on the airline's board of directors.
Sir Stelios pointed to the company's share price progress over the last 10 years and lack of dividends to back his criticism of the company's strategy.
He said: "How can you buy 200 aircraft with shareholders' money and create no wealth for shareholders?"
A long-running battle between Stelios and Easyjet's board had already caused the departure of a number of the airline's executives, including Andy Harrison, who resigned as chief executive in December.
Easyjet said on Friday the board had agreed unanimously on the strategy.