The privately-owned airline, which is based at Humberside airport and also operates flights from Leeds Bradford airport, recently took delivery of a 37-seater Embraer 135 and this week leases another.
The airline has served Yorkshire's business community for almost seven years, providing links to Aberdeen and Southampton.
Eastern Airways also has eight 50-seater Saab 2000s in its fleet and is the largest operator in the world of the 29-seater Jetstream 41 with 20 of the aircraft.
"The Embraer jet complements our fleet and gives us tremendous flexibility as we can offer 29, 37 and 50-seat aircraft to the private charter market," said Eastern Airways' chief operating officer Chris Holliday.
"We have operated Embraers in the past and the time is now right to reintroduce the fast 37-seater to fill a gap primarily in the charter market serving central and eastern Europe."
The airline agreed a lease deal with GE Capital Aviation Services for the Embraer jets.
Delivery of the first aircraft took place last month with the second aircraft expected on Wednesday.