今、飛行機の乗り換えだ。今まで飛行機８時間乗って、乗り換えてこれから又２時間だ。

、。、。

Right now, I'm transferring planes. So far I've been on a flight for 8 hours, and after transferring there's another 2 hours to go.

Literal

Now, airplane [of-の] transfer [copula-だ]. Until-now airplane 8 hours ride, transfer from-now again 2 hours [copula-だ].

Travel-diary register. 乗り換え 'transfer' is the verbal noun from the compound verb 乗り換える 'to change vehicles.' The sentence uses multiple nominal predicates with だ: '[state] だ。' — no verb needed, just declaring 'it is [state].' 又 'again' is the slightly formal kanji for また, common in personal writing. The opening of each sentence with a time marker (今, 今まで, これから) organizes the narrative along a timeline.