The company said some 15 percent of its flights would be cancelled on Friday, the first day of the two-day strike.
Unions representing air stewards and air stewardesses working for Hop! believe many staff will follow their call to stage a walk-out.
Hop! which was set up in 2013 by Air France as a rival to budget airlines like easyJet and Ryanair runs 600 flights daily to around 50 airports in France and around Europe.
Last year the company transported 13 million passengers.
The industrial action is caused by union concerns over job security. They claim their jobs are threatened by bad management of pilots, who are leaving the airline to work at Air France.
The company has suffered losses in recent years but is hoping to break even in 2017.
Not only does it face competition from other low cost airlines but France’s high-speed TGV rail network also entices passengers away from its many internal routes.
Hop! closed its Paris to Strasbourg route in July when the TGV opened a new high-speed connection between the capital and the city in the east.
The company is to launch a weekend card for €69 that will give passengers 25 percent discounts on internal routes.
Passengers are advised to check with the airline to see if their flight is impacted by the strike.