Aircrraft turbos are not really all that big...they are not there to add gobs of power like a car...they are mainly used to add positive pressure to the intake at high altitudes...granted some do boost, and they boost very well...and they do add a lot of take off power...but not in the since that people whodeal with cars think of.
aircrafts main goals are to fly longer, higher, faster, and use as little gas as possible, cause gas is just heavy...and at over 6 lbs per gallon.....a lot of gas is needed to take a 20,000 lb plane a long distance.
So a fine medium is found, and used....flight is more of an economical sport...or a business.. Use more gas, get there faster, but have to land many times to get gas=not good. Fly with just the right boost, use just the right amount of gas, and not waste any gas or useable fuel load...and save money...aircraft gas is not cheap...and infact...plane tickets go up....when the price of gas goes up...
And there was something on the news a few days about how most airlines are chargeing fat people more money...cuase they have to use more gas to get their lard asses in the air.