David Morgan to take over as interim COO, reporting to EasyJet chief executive Johan Lundgren.
Bellew resigned on Friday (1 July), easyJet confirmed on Monday (4 July), "to pursue other business opportunities".
He joined easyJet from Ryanair in July 2019.
His resignation comes amid a tumultuous period for easyJet and a number of other European carriers with staff shortages continuing to cause significant disruption for aviation operations.
The easyJet board said they wanted to thank Bellew for his hard work and wished him well.
Morgan has been with easyJet since 2019, and previously served for almost a year as interim COO.
"I would like to thank Peter for his hard work and wish him well," said Lundgren. "Everyone at easyJet remains absolutely focused on delivering a safe and reliable operation this summer.
“I am pleased that operations will be in the very capable hands of David Morgan who can move seamlessly into this role having previously led the operation as interim chief operating officer throughout 2019.
“David has significant experience and deep knowledge of the business and operation and will provide strong leadership for the airline this summer.”
In a statement, the airline added: "EasyJet remains absolutely focused on our daily operation and continues to monitor this very closely, having taken pre-emptive action to build further resilience for the summer due to the current operating environment.
"The airline continues to operate up to 1,700 flights each day and carry up to 250,000 passengers."
