Of course I cannot tell much because that would be revealing my business model, but there are some factors to consider. New planes can get you image in high 80s low 90s in after just couple of weeks. That image can actually help you with up to 20 percent margin over default price depending on severe class seat and service, while still maintaining the same flight rating. In other words a brand new 320 with a good seat and service and excellent image, can draw up to 20 percent increase in price over default depending on the class of service. Of course its not that simple as just increasing the price with new aircraft, but the point is, age makes a huge difference for image, and image makes a huge difference for flight rating.
2 green bars is like image 20 to 40. That’s peanuts in image rating compared to 90 you can get with new aircraft.
You can start with old aircraft and then switch to new ones but your image will drag you down. My USA airline started with old MD80s and 737 classics and I started to switch at like 250 planes, with image at around 30, now 14 months later and 1100 new planes more, the image is still only in low to mid 80s (5 green bars). Those old planes and low image will drag you down forever. Compare that with a sub, new planes, no terminals, image in the low 90s after two weeks.
If you want to start with old planes, by all means do that because you can get a lot of connections. But find a point where you need to stop growing and start replacing, you may need to stop the growth for a month while you replace, but the money saved on maintenance will pay for your leases of new planes. It will. And best if you reschedule into a new sub.
Remember, all the past image ratings as a result of all flights in the past form part of the current rating. If you have a flight with image rating 1, no matter what you do and how many flights with image 99 you fly, you will still have lower average image than somebody who has a flight with image rating 10, or 20 or 30, plus the 99 image rating flights. That’s just math.
P.S. You cannot get red bars in airline image. Even a 50 year old plane will make you one green bar of image for your airline, because 0 is absolute minimum, and anything flying gives you an image rating higher than 0. The difference is between 0.01 and 99.9, though.