What you're dealing with is an ADA that's been weaponized. It really *is* all or nothing, not just reasonable accommodation, on pain of very expensive lawsuits, when buying or building something by a government agency or otherwise used by or open to the public. To some degree, even private homes and historic sites are subject to it. You can pay me now (by building it so it's fully accessible) or pay me later (rebuilding it to be fully accessible, and paying a predatory lawyer's settlement/fees too). So single-level cars with full-width passage between, and narrow seats if seating capacity must be maintained, are pretty much mandatory. And surely, by now, if you do any flying, you'd be used to narrow seats! •`_´•