Ms Ourmieres-Widener, an executive at Air France before she ran fellow regional operator CityJet between 2010 and 2015, takes over next month.
She will lead the carrier’s expansion into London Heathrow airport. It has operating slots forfeited by British Airways.
Regional airlines lack the efficiencies of discount specialists, such as Ryanair, flying smaller aircraft between minor cities.
Under Mr Hammad, Flybe abandoned its plans to act as a consolidator for the sector across Europe, cutting routes, firing hundreds of workers, and cancelling plane orders to focus on UK services and code-sharing deals with other carriers.
Flybe will commence flights from Heathrow to Edinburgh and Aberdeen next March, using slots that IAG’s British Airways relinquished to stop it having a monopoly over the services, following its takeover of the former British Midland.
Other than landing and passenger charges, the regional operator will not have to pay for the positions, which were utilised by Aer Lingus on behalf of Virgin Atlantic Airways under the Little Red brand before the plan was dropped.
Ms Ourmieres-Widener, who, at CityJet, ran the biggest operator at London City airport, where Flybe also has an expanding presence, is a rare female airline chief, though the second at a major UK carrier, alongside EasyJet CEO Carolyn McCall.
She joins from American Express Global Business Travel, having spent less than two years as head of global sales at the corporate bookings provider. Ms Ourmieres-Widener “brings extensive experience of aviation and travel, as well as deep knowledge of the UK regional aviation market”, said interim CEO Simon Laffin, who resumes his role as Exeter-based Flybe’s chairman.
Separately, CityJet said, earlier this month, that it had scrapped talks about buying rival, Stobart Air, which operates major routes for Aer Lingus and Flybe.
Stobart confirmed that talks over a potential collaboration and a possible ownership deal were at an end.
A spokesman for CityJet said it had ended the acquisition talks because of the protracted negotiations.