The pilots take workers to and from the oil platforms
About 200 staff from CHC Scotia are threatening to walk out unless their salaries are increased to match those of fixed-wing pilots.
The British Airline Pilots Association (Balpa) say the difference in wages is leading to trained staff deserting the industry.
A helicopter pilot with ten years service can expect to earn about £51,000 compared with £70,000 for fixed-wing crew.
Most of the firm's work involves transporting personnel and equipment to oil rigs from bases in Hull, Blackpool, Norwich and Aberdeen.
John Moore, Balpa's principal negotiator, said: "The strong ballot result shows that our members are not willing to stand by and watch a generation of young, highly-skilled helicopter pilots haemorrhage away into the fixed-wing sector.
"Our members still wish to resolve this matter through a negotiated settlement.
"However, the future of their industry is at stake and they are prepared to take strike action in order to safeguard it.
'Very disappointed'
"Once again, I call on CHC Scotia to put forward a revised offer to allow direct negotiations to reopen."
The union said it was still considering when the strikes should take place.
A spokesman for CHC Scotia said: "We are very disappointed at the result of the ballot.
"We have contingency measures in hand to try to minimise the impact of any industrial action on the offshore workforce.
'Generous offer'
"At the same time, we remain fully committed to reaching a mutually-suitable agreement with Balpa and, as has been the case throughout, we are willing to use independent mediation to achieve a resolution.
"We felt the offer we had put before our pilot workforce was an extremely generous one, resulting in significant salary increases over the period to May 2004."
CHC Scotia serves oil platforms owned by some of the UK's largest offshore operators, including BP, ExxonMobil, Talisman, TotalFinaElf and Kerr-McGee.