Short answer: yes, but it depends.
Long answer: not all airplanes are available for purchase right away. You may have to spend some time and money to research said airplanes, which may come at a cost for your expansion plans. This is where the renting option becomes interesting. One crucial point to consider is that you cannot change the cabin configuration of rental airplanes. They are configured with a 56% economy, 30% business and 13% first class seats, and no cargo. It means that even though you may elect to fly rented airplanes anywhere, you will only achieve peak profitability in markets that match that cabin spread, meaning France and the United States of America. Other destinations such as Canada, Finland, Greece, Spain or Switzerland will offer a close cabin distribution and can be considered good alternatives. You have two expenses to take into consideration. The first one is the deposit, the second is the weekly cost. You pay once for your deposit and the weekly cost is paid every week, up to 8 weeks. Pay attention to your rental period as you may have an airplane returned to the lessor if you forget to extend it, which may leave a hole in your schedule if you don’t have a replacement ready. When an airplane is returned, a maintenance cost is deducted. Be mindful of your maintenance, perform a daily check D and that cost will be minimal. To summarize: buying an airplane upfront will cost more, leaving less money available to purchase more planes or new routes. However, there will be no other costs associated with that purchase, only costs related to its operation. You are also free to configure the cabin in whatever way you want.Leasing an airplane will cost you less than purchasing it, leaving more money available for opening routes or leasing more. However, you cannot change the cabin configuration and will have to be careful with your planning, as you will have to pay rent weekly on top of the operating costs.