A.T. Robertson Commentary Matthew 17:4

"And Peter answered, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, I will make here three tabernacles; one for thee, and one for Moses, and one for Elijah." — Matthew 17:4 (ASV)

And Peter answered (αποκριθεις δε ο Πετρος). "Peter to the front again, but not greatly to his credit" (Bruce). It is not clear what Peter means by his saying: "It is good for us to be here" (καλον εστιν ημας ωδε εινα). Luke (Luke 9:33) adds "not knowing what he said," as they "were heavy with sleep." So it is not well to take Peter too seriously on this occasion. At any rate he makes a definite proposal.

I will make (παιησω). Future indicative though aorist subjunctive has same form.

Tabernacles (σκηνας), booths. The Feast of Tabernacles was not far away. Peter may have meant that they should just stay up here on the mountain and not go to Jerusalem for the feast.