Ryanair reported a 7% fall in profits in the six months to September and refused to rule out closing bases and cutting services amid “excess capacity in Europe”.

The carrier blamed overcapacity “along with strikes” and “staff shortages” at air traffic control (ATC) for a 3% fall in average fares year on year, yet Ryanair’s traffic rose 6%.

Ryanair chief executive Michael O’Leary said: “Our traffic was repeatedly impacted by the worst summer of ATC disruptions on record.”

In a statement the carrier noted: “The risk of a hard ‘no-deal’ Brexit is rising.” It expressed hope that the planned transition agreement from March 2019 to December 2020 “will be extended”.

However, in the event of a hard Brexit, Ryanair said: “The board will restrict the voting rights of non-EU shareholders and confine them to selling shares only to EU nationals, to ensure Ryanair remains majority owned by EU shareholders.”

The carrier maintained its full-year forecast of up to €1.2 billion in profit but warned: “This remains heavily dependent on fares not declining further, the impact of significantly higher fuel prices, the absence of unforeseen security events, ATC and other strikes and the impact of Brexit developments. We cannot rule out further base closures or capacity cuts if oil prices rise or air fares fall.”

The carrier has so far cut winter capacity by 1%.

Ryanair noted the recent failures of six small airlines in Europe, including Cobalt Air and Primera Air, saying: “We expect more failures this winter.” It noted: “Trading may be positively impacted by other airline failures.”

The airline suggested it had made “good progress with union negotiations” despite continuing strikes by pilots and cabin crew in several countries and said: “We can manage strikes although we do our utmost to avoid them. [But] we cannot rule out occasional industrial action.”