The "best" suitcase material depends on your specific travel priorities: durability, weight, or flexibility. Polycarbonate is widely considered the gold standard for hard-sided luggage in 2026. It is a high-tech plastic that is incredibly lightweight yet flexible enough to "flex" and absorb impacts, preventing the shell from cracking under the pressure of baggage handling. For travelers who prioritize maximum protection for fragile items, Aluminum is the ultimate choice; it is nearly indestructible and provides a sleek, premium look, but it is significantly heavier and much more expensive. On the other hand, Ballistic Nylon or Polyester (Soft-side) remains the favorite for "over-packers" because the fabric can stretch and often includes external pockets for easy access to documents. Soft-side bags are also better at squeezing into tight overhead bins. If you are a frequent flyer, a Polycarbonate-Aluminum hybrid (a polycarbonate shell with an aluminum frame) offers the best of both worlds: the lightweight nature of plastic with the rigid, secure latch system of metal. For budget travelers, ABS plastic is common but tends to be more brittle and prone to cracking over time compared to pure polycarbonate.