If you have ever boarded a flight in the last boarding group and watched a gate agent tag your carry-on for the cargo hold, you already understand the problem. Overhead bin space on most commercial jets was designed decades ago, when roller bags were smaller and fewer passengers tried to avoid checked-bag fees. Now two major U.S. carriers are tearing out those old compartments and bolting in replacements large enough to hold significantly more luggage, an aircraft-by-aircraft overhaul that is already underway and expected to spread across hundreds of planes through mid-2026.
United tackles the regional jet that needed it most
United Airlines became the first carrier to install new, larger overhead bins on the Embraer E175, one of the most widely flown regional jets in North America. According to the airline’s announcement, distributed via PR Newswire in early 2024, the retrofit adds room for up to 29 more carry-on bags per aircraft, an 80 percent increase over the original configuration. On a plane that typically seats 70 to 76 passengers, that is a dramatic shift: bins that once ran dry well before the last boarding group now have capacity for nearly every traveler’s bag.
The key engineering change is orientation. The redesigned bins accept standard roller bags wheels-first, standing upright rather than lying flat. That single adjustment unlocks the extra volume without requiring airlines to tear into sidewalls or raise ceilings. For passengers on United Express routes, where gate-checked bags have long been a near-certainty on full flights, the difference should be immediately visible: deeper compartments with pivoting doors that swing up and out of the way.
United operates dozens of E175s through its regional partners, though the airline has not published a tail-number list or a completion schedule showing how many jets have already been converted as of mid-2026. The pace depends partly on maintenance windows and partly on how quickly aircraft can cycle through hangars for the installation work.
Alaska and Boeing scale the fix to the 737
On the mainline side, Alaska Airlines signed on as the launch customer for Boeing’s Space Bin retrofit program for the 737-900ER specifically, targeting in-service jets equipped with the Boeing Sky Interior. Each upgraded Space Bin holds six standard roller bags instead of four, a 50 percent gain per compartment, according to Boeing’s own product page for the Space Bin. Boeing offers the Space Bins both as a factory option on new 737 MAX deliveries to multiple airlines and as a retrofit kit for older 737NG and 737 MAX aircraft already in service.
That 50 percent increase per bin compounds quickly down the length of a narrow-body cabin. A typical 737-900ER has dozens of individual overhead compartments; adding two more bags to each one translates into space for scores of additional carry-ons across the aircraft. Alaska, which operates a largely all-737 fleet, is positioned to roll the upgrade across a significant share of its network, though the airline has not disclosed a public timeline or total aircraft count for the program.
Boeing markets the retrofit as a packaged solution for 737 operators worldwide, but fleet-wide adoption figures across all customers have not appeared in the company’s public materials. For travelers, the practical tell is the same as on the E175: bins that are noticeably deeper and allow bags to stand on edge rather than lie flat.
Every bin swap needs federal sign-off
Neither airline can simply order parts and start swapping hardware on its own schedule. Any physical change to an aircraft’s certified design in the United States requires a Supplemental Type Certificate, or STC, from the Federal Aviation Administration. The STC confirms that the modification meets safety standards without compromising structural integrity, weight limits, or emergency-evacuation performance.
Overhead bins are both structural and functional components, so the review is more involved than it might sound. Heavier, deeper compartments change how loads are distributed in the cabin ceiling and can affect how quickly passengers reach emergency equipment or move toward exits during an evacuation. The FAA reviews stress analyses, evacuation modeling, and detailed installation procedures before granting approval. Only after that sign-off can an airline fold the modification into its maintenance planning and begin cycling jets through hangars.
That regulatory layer is worth noting because it separates these upgrades from cosmetic cabin refreshes like new seat covers or mood lighting. A certified bin redesign has passed an independent federal engineering review before a single passenger encounters it.
What the airlines have not said yet
For all the enthusiasm in airline and manufacturer announcements, several important details remain unpublished. Neither United nor Alaska has released operational data tying the larger bins to measurable boarding-time reductions or fewer gate-checked bags. Boeing’s marketing materials frame the bins as a fix for boarding delays and passenger complaints, but no controlled study or airline operations report has surfaced to quantify the effect.
Whether the investment in engineering, certification, and installation actually pays off in shorter turnaround times at the gate or simply reduces passenger frustration without changing airline economics is still an open question. The logical case is straightforward: more cubic inches per bin means more bags fit, which means fewer carry-ons get sent to the cargo hold. But the operational proof has not been made public.
It is also unclear whether other large U.S. carriers plan similar retrofits. Delta, American, and Southwest all operate aircraft types eligible for comparable bin upgrades, and all face the same passenger complaints about overhead space. Any announcements from those airlines would signal that the industry views bigger bins not as a competitive perk but as a baseline expectation.
How to tell if your next flight has the new bins
Neither carrier has launched a passenger-facing tracker or published which specific tail numbers have been converted. The simplest way to tell is visual: look for deeper compartments with doors that pivot upward and bins that clearly accommodate a roller bag standing on its side, wheels facing in. If your bag slides in upright without a fight, you are probably on a retrofitted jet.
Until the rollouts are further along, passengers who absolutely need overhead space will still benefit from boarding early or purchasing priority access. Larger bins reduce the odds of a gate check on a full flight but do not eliminate them entirely. And travelers who split time between modified and unmodified aircraft may start to notice a real contrast during boarding, with retrofitted cabins feeling noticeably less chaotic simply because there is less competition for a finite resource overhead.
For now, the takeaway is concrete even if the fleet-wide data is not. On the specific aircraft where these larger bins have been installed and certified, passengers can expect more room for standard carry-ons, fewer surprise trips to baggage claim, and a boarding process that feels a little less like a land grab at 30,000 feet.
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*This article was researched with the help of AI, with human editors creating the final content.
