Aer Travel Pack vs Travel Pack Small: which size fits you

Start at the scale, not the liter count

The number that decides your bag sits on a luggage scale at the gate. Fly a Wings Air hop between Indonesian islands and Lion Group's rule is 7 kg of cabin baggage, bag included, in a box no bigger than 40 x 30 x 20 cm. AirAsia gives you the same 7 kg across both the bags you carry on. ^{8, 7}

An empty Aer Travel Pack 4 35L weighs 3.90 lbs, which is 1.77 kg, or 25.3 percent of that allowance before the first shirt goes in. The 28L weighs 3.52 lbs and buys back 0.17 kg. These are small numbers. They are also the ones that settle which Aer you should own. ^{3, 2}

So this page puts Aer's two current sizes side by side on Aer's own published figures, read from its store on 25 September 2026, and measures both against the cabin rules six budget carriers publish. Prices are US dollars as each maker shows them. ^{3, 2}

Which Aer pack replaced the Travel Pack Small?

Aer answers this on its own product page, and the replacement is a 28L rather than a second 35L.

Aer's page for the Travel Pack 3 Small says it plainly: 'There is a newer version of this item: Travel Pack 28L.' That newer version sells as the Travel Pack 4 28L at USD 239. The legacy Small is still in the store at USD 229, which is USD 10 cheaper and 0.27 lbs heavier. ^{1, 2}

The big end reads the same way. The Travel Pack 3 is USD 249 and 4.12 lbs; the Travel Pack 4 35L that replaces it is USD 259 and 3.90 lbs. Ten dollars more, 0.22 lbs less to carry. ^{13, 3}

Each current size comes in three shells, so the real choice is six packs wide. Cordura is the standard. X-Pac adds USD 30. Ultra400X costs USD 50 more and weighs the least: the Ultra 28L is 3.28 lbs, the lightest pack in the line. ^{14, 15, 2}

How much do you give up going from 35L to 28L?

Seven liters, 0.38 lbs and four inches of total girth. Multiply the sides and the 35L is a 2,612 cubic inch box; the 28L is 1,964. The smaller pack is 75.2 percent of the bigger one and gives up 649 cubic inches, roughly a pair of shoes and a fleece. ^{3, 2}

Both sizes carry the same computer. Aer prints one line on every current Travel Pack 4 page: a padded, suspended laptop pocket that fits up to 16 in. Drop to the 28L and the machine still goes in. What shrinks is clothes. ³

Aer publishes liters, inches and pounds, and leaves the packing list to you, which is the honest position: a two-week kit that fits one person's 28L overflows another's. Shoes and a jacket decide it, and so does how often you do laundry. A month in one apartment turns laundry into a Tuesday errand and makes the 28L plenty; MMT's comparison of monthly stays against short bookings prices that kind of trip.

Which budget airlines will take either pack?

Six carriers, each figure from the airline's own baggage page except LATAM, read on 25 September 2026.

On size, both packs clear Volaris, Avianca, LATAM and AirAsia, and both are over the line at Lion Air and Wings Air. The 35L's longest side is 54.5 cm. Volaris allows 55 x 40 x 25 cm, Avianca 55 x 35 x 25 cm including wheels and handles, AirAsia 56 x 36 x 23 cm. Lion Group allows 40 x 30 x 20 cm. ^{4, 5, 7, 8, 3}

The fare changes the answer as much as the size does. On Volaris a carry-on arrives with the Plus fare and above; the Zero fare buys a personal item alone. On Avianca the carry-on is a paid add-on at the Basic fare, while the personal item rides free on every fare. Wingo includes a 12 kg cabin bag from Go Standard up and a 23 kg checked bag from Go Plus up, 25 kg to and from Mexico. ^{4, 5, 19, 18}

These six carriers cover a lot of ground: Volaris across Mexico, Avianca and Wingo out of Colombia, LATAM down the Andes, AirAsia and Lion Group across Southeast Asia. Plan the trip around them with MMT's Mexico travel guide and Indonesia travel guide.

The 7 kg carriers pick your size for you

Kilograms are where a one-bag trip breaks, and the empty pack spends them first. AirAsia allows two cabin items with a combined weight of 7 kg: a bag up to 56 x 36 x 23 cm and a personal item up to 40 x 30 x 10 cm. The pack itself counts. An empty Travel Pack 4 35L leaves 5.23 kg for your things; the 28L leaves 5.40 kg. ^{7, 3, 2}

Lion Group is tighter again: 7 kg, and a cabin box of 40 x 30 x 20 cm that leaves both Aer packs at the gate. Wings Air's propeller routes carry no free checked allowance on a single-sector ticket, so price the hold into the fare before you book. ⁸

When the kit is heavy by nature, the pack is the small line in the sum. MMT's guide to baggage costs for your own dive gear and its comparison of ski luggage fees against local rental price the alternative to carrying it.

Is the Aer Travel Pack waterproof?

Aer answers this on its own FAQ, and the answer is no. 'All of our bags are triple-coated with polyurethane for water-resistance,' Aer writes, and then draws the line itself: 'water-resistant' does not mean 'waterproof' because the seams are not taped, so water can seep in under extended exposure to rain. Aer recommends a rain cover or an umbrella for a shower. ⁹

That holds for the upgrades too. Aer credits VX-42 X-Pac with structure, water resistance and a slightly stiffer feel beside Cordura, and Ultra400X with the highest strength-to-weight ratio of the three while staying the lightest. Plain 1680D Cordura earns its place on toughness and abrasion resistance. The polyurethane coating does the water work on all three. ⁹

What does Aer's lifetime warranty cover?

Manufacturing defects, for the life of the product, repaired or replaced at Aer's discretion. Aer's warranty page sets it out: 'We proudly offer a lifetime warranty that covers any manufacturing defects in materials or workmanship throughout the entire lifespan of the product.' ¹⁰

• Covered: defects in materials or workmanship, for as long as the bag lasts, with repair or replacement Aer's choice. ¹⁰
• Left out: normal wear and tear from regular use, the natural breakdown of colors and materials, UV degradation, rips, tears, punctures and abrasion. ¹⁰
• Shipping: a US claim in the first year travels back at Aer's cost; after a year the return postage is yours. ¹⁰
• Turnaround: three to four weeks is typical, and six weeks or more in Aer's busy season. ¹⁰

Cotopaxi's lifetime warranty on the Allpa 28L reads the same way: defects in, wear out. A lifetime warranty on a travel bag is a promise about the stitching, so read it as one. The zipper pull you wear through in five years of airports is yours to replace. ^{11, 10}

Cheaper alternates, and who each one suits

Two packs undercut Aer's 28L on price, and each gives something up. Cotopaxi's Allpa 28L Travel Pack is USD 205, USD 34 under Aer, at 19 x 12 x 9 in with a water-resistant shell. Matador's 24L Adventure Pack is USD 199, USD 40 under Aer, and 4 L smaller. ^{11, 12, 2}

• Aer Travel Pack 4 28L, USD 239. The pick if you carry a 16 in laptop, want the clamshell opening and the lifetime defect warranty, and fly the 7 kg carriers often enough to care about 1.60 kg. ^{2, 10}
• Cotopaxi Allpa 28L, USD 205. The pick when weight rules the decision. It saves 0.47 kg against Aer's 28L at the same 28 L, takes a 15 in laptop, and carries its own lifetime warranty on defects. ¹¹
• Matador 24L Adventure Pack, USD 199. The pick for a shorter trip or a second bag, at 24 L and weatherproof in Matador's own words. Get its dimensions and weight in writing before you buy for a tight cabin box. ¹²
• Aer Travel Pack 3 Small, USD 229. Still in Aer's store, USD 10 under the current 28L and 0.27 lbs heavier, with a narrower 7.5 in depth. Worth a look when the price matters more than the ounces. ^{1, 2}

Which size should you buy?

Buy the 35L unless a 7 kg cabin limit shows up in your normal flying. It costs USD 20 more, weighs 0.38 lbs more and holds 649 cubic inches more, and for one bag doing a month that is the better trade. When AirAsia, Lion Air or Wings Air fill most of your itineraries, the 28L's 1.60 kg and 49 x 32 x 20 cm shape leave more of the allowance for clothes. ^{3, 2, 7, 8}

1. 01

   Weigh your real packing list

   Load the bag you own for the trip you actually take, weigh it, then subtract the bag. Add 1.77 kg for the 35L or 1.60 kg for the 28L. That total is what a gate agent sees. ^{3, 2}

2. 02

   List the airlines in your next year

   Volaris and Avianca give you 10 kg, LATAM 12 kg in economy, and all three take either pack on size. AirAsia and Lion Group give you 7 kg, and Lion Group's 40 x 30 x 20 cm box takes neither. ^{4, 5, 6, 7, 8}

3. 03

   Pick the size, then the shell

   Cordura is the standard at USD 259 and USD 239. Ultra400X saves 0.34 lbs on the 35L and 0.24 lbs on the 28L for USD 50 more, which on a 7 kg limit is 0.11 kg of clothes bought back. X-Pac sits between at USD 30 more and adds waterproof zippers on the 35L. ^{3, 2, 17, 15, 16, 14}

4. 04

   Check the legacy pair before you pay full price

   The Travel Pack 3 at USD 249 and the Travel Pack 3 Small at USD 229 are still in the store, USD 10 under their replacements and 0.22 lbs and 0.27 lbs heavier. ^{13, 1}

5. 05

   Add a rain cover either way

   Aer calls every bag it makes water-resistant and recommends a cover or an umbrella for rain. Budget for one whichever shell you choose. ⁹

One more thing to settle before the card comes out: try the pack on loaded. Aer publishes dimensions, volume and weight, and the 28L's back panel is 2.25 in shorter than the 35L's. For a torso range, ask Aer or the retailer, and walk around the shop with weight in the bag. ^{3, 2}