Video Overview

Pack Hacker’s two-week review format is one of the most trusted benchmarks in travel gear, and this comparison video applies that same rigor to a head-to-head matchup of the Aer Travel Pack 4’s two sizes: the 28L and the 35L. Both packs share Aer’s refined design language and premium materials, but the size difference drives meaningful differences in carry behavior, daily usability, and travel versatility. Pack Hacker walks through external features, the harness system, fit notes, secondary compartments, and the main compartment for both — giving you the full side-by-side picture. Whether you’re trying to decide between sizes or just curious how Aer has evolved their flagship travel pack, this is the definitive comparison.

Items and/or Gear Mentioned in the Video

• Aer Travel Pack 4 28L – Purchase on Amazon
• Aer Travel Pack 4 35L – Purchase on Amazon

Pack Hacker scores the 28L at 8.7/10 and the 35L at an exceptional 9.3/10 — a rare high mark that signals the larger variant has genuine advantages worth understanding. The 28L weighs 3.45 lb and keeps a tighter footprint for urban commuting and weekend carry, while the 35L at 3.56 lb unlocks a full week of travel capacity without jumping to a checked-bag footprint. Both use Aer’s latest materials and construction, making the choice almost entirely about volume needs.

Editor’s Insight

A 0.6-point gap between two size variants of the same pack is unusual, and Pack Hacker’s scores here tell a story worth unpacking. The Aer Travel Pack 4 35L earning a 9.3/10 — against the 28L’s already-strong 8.7/10 — suggests that for Pack Hacker’s testing methodology and real-world travel use cases, the larger pack resolves some constraints the 28L runs into. That’s not a knock on the 28L, which is still an excellent bag. It’s a signal about what type of carry each version is optimized for.

Aer built its reputation in the EDC and travel communities by making bags that appeal to professionals who want to carry less but carry better. The Travel Pack 4 represents years of iteration on their flagship travel-focused design — refined hip belt system, laptop compartment placement, organization layout, and material quality are all outcomes of that process. Both the 28L and 35L inherit that evolution fully.

The 28L is the pure daily carry and weekend warrior option. At 3.45 lb and 28 liters, it stays within the range where you’re not fighting the pack — you’re working with it. The tighter volume forces intentional packing, which many experienced travelers prefer. You never check a bag, you never slow down at airports, and you carry exactly what you need. For business trips of two to three nights or aggressive one-bag travel, the 28L is a precision instrument.

The 35L is a different proposition. Seven additional liters sound modest until you start packing for a week. That extra volume is where the 35L earns its 9.3/10 — it absorbs a full week’s worth of clothing, tech gear, and daily carry accessories without requiring you to sacrifice or compress. For international travel of five to seven days where checking a bag is either expensive or impractical, the 35L’s capacity becomes a genuine advantage. The 0.11 lb weight difference over the 28L is essentially negligible.

The harness system is one area Pack Hacker dedicates meaningful time to in their comparison, and rightly so. A 35L pack carrying a full week of gear asks significantly more of its shoulder straps and hip belt than a lightly loaded 28L. If Aer’s harness holds up under the 35L’s load — and Pack Hacker’s 9.3 score suggests it does — that’s a meaningful engineering win. The fit notes section of the video is worth watching in full if you’re between sizes, because both packs can feel different depending on your torso length and build.

Secondary compartment organization is often where travel packs reveal their true character, and both variants of the Travel Pack 4 carry Aer’s deliberate pocket architecture. The question for comparison shoppers is whether the 35L’s additional main compartment volume comes with well-proportioned secondary storage, or whether the smaller pockets feel undersized relative to the expanded main. Pack Hacker’s chapter breakdown addresses this directly at the 6:56 mark.

For EDC-first buyers who also travel occasionally, the 28L is likely the right call — it performs as a daily carry bag without feeling oversized in urban settings, then doubles as a capable travel pack for short trips. For those whose primary use case is travel and who happen to also use it for daily carry, the 35L’s superior trip capacity justifies the slightly larger footprint. Aer’s construction quality means whichever you choose will last for years, making this a decision worth taking seriously.

Full credit to Pack Hacker for this format — side-by-side comparisons of size variants are some of the most practically useful content in the gear review space, and doing it with two weeks of real use rather than a five-minute unboxing makes the scores meaningful. Watch the full video for the complete walkthrough and reach your own conclusions on which size matches your carry habits.

Closing Remarks

The Aer Travel Pack 4 comparison comes down to a simple framework: 28L for urban daily carry and short trips, 35L for week-long travel without checking a bag. Pack Hacker’s scores — 8.7 vs 9.3 — favor the larger variant, but both are outstanding bags. Drop a comment below: which size would work better for how you travel? Note: affiliate links above support the blog at no cost to you.