。
This time next week, I'll be on an airplane.
Literal
Next-week [possessive-の] now-around [topic-は] airplane [possessive-の] inside is.
今ごろ ('around now / this time') combined with 来週の prefixes for 'this time next week.' ~の中 ('inside of X') is the standard locative for 'within / in.' A compact statement of future state with implicit copula continuing.