Bolivia has summoned the ambassadors of France, Spain, Portugal and Italy to explain why their countries blocked President Evo Morales' jet last week.
Mr Morales was flying home from Moscow when his plane was forced to reroute to Vienna, amid rumours that US fugitive Edward Snowden was on board.
Mr Snowden, a former CIA contractor, is wanted by the US on charges of leaking secrets about US surveillance schemes.
The European countries have variously denied closing their airspace.
Mr Snowden was not on the flight, and is still believed to be in the transit area of Moscow's Sheremetyevo airport.