No, actually...we ARE talking about aborted takeoffs. What do you think happens when a 757 taxis into position, the pilot flicks on the strobes, brings the throttles up to 92% N1...but then the EGT or N2 gauge doesnt play along? Hes pulling off the runway, parking on the taxiway and going to run some checks, thats what. And then...proably going to pull up to the company tarmac where a repair crew will check over the bird right then and there with the passengers still on board. And after two hours or so, the ground crew will give him the go ahead or they will cancel the flight depending on what they find.
Again...repairs are dont on the fly MOST of the time...beucase an airline's planes have to do that funny thing called "generate revenue." And do do that, they have to do what they are built to do...fly. A lot. Almost constantly. To illustrate how much work an airliner gets further...next time you fly, when the engines are started if you DONT smell a whiff of kerosene (Jet A, more or less), the plane youre on was in the air probably not even an hour or two ago. And Id guarantee you wont experience this on 90% of the flights you fly.