Those are steep stairs and there are many of them. I can imagine an old injury can bother an older American at an inopportune time.
There are other ways on that jet. President Biden should feel free to use them.
FDR didn’t worry about going up stairs and looking young and tough. He was respected for his age and wisdom.
America loves President Biden and if he needs to end the matcho act on the stairs to his jet, I imagine most Americans will feel good about it.