What external SSD should I use for Time Machine on a MacBook Air?

Regarding the MacBook Air: A Samsung T7 or Crucial X9 is all you need. Any reputable USB 3.2 Gen 2 or Thunderbolt 3 SSD works fine. The Samsung T7 is fast, tiny, silent, and doesn’t get hot; the Crucial X9 is a cheaper alternative. Get at least 1TB and skip HDDs — SSDs are faster and more reliable for backups.