So, for a start, the Boeing 757 was a hit in the airliner market. A long range single-isle aircraft but, they are showing their age. If you fly on one it is most likely to be 30 to 50 years old. So multiple companies have attempted to replace it, Boeing tried by making the 737 but it has nowhere near the range of the 757. And somewhere around 2025 they will release the 797 most likely to Delta-Airlines, though I think it will fail, it just isn’t the right size to me. Now moving on to Airbus, they tried by making the A310, but it failed miserably so skip. Now to McDonell-Douglas, they dont really make that kind of aircraft so again, skip. Now to Bombairdier, they only make private jets so once more, skip now the last one, Embadaer their C-series are very similar to the 757, the perfect company for the job! Let me know if you agree with this or disagree; it would be nice to hear an explanation if you disagree! Have a nice day!