Flying Free or Burdened with the Beast? A Dilemma

We love our Clek Foonf. Like, really really love it. So much so that we own two of them. Some of our favourite features are the ease of installation, the safety, the comfort (Little L falls asleep in it all the time!), and the high profile.

However, we do not love its heavy weight (38 lbs in RF mode with the attachment, 33 lbs in FF), nor do we love the idea of bringing it on a 6-hour flight to Maui. Lugging the Foonf and our carry-on and Little L and her umbrella stroller would be too painful to do. That's a lot of stuff.

Checking our Foonf (or any carseat, for that matter) is not an option because most checked car seats are considered "as good as crashed" to safety techs, because of the airline's lack of care when handling them in the cargo area. We cannot risk our beloved chair being damaged.

However, it's debatable if the Foonf would even fit on an airplane; because it does have this wonderfully-high profile, the Foonf is a major beast to install on a narrow window seat in rear-facing mode. In front-facing mode, we would need a tether, which is not available on a jet.

So basically, even though we love the idea of having the Foonf with us for two weeks in Maui, it's simply not practical.

Some have suggested that we just take the CARES harness in-flight and rent a carseat at our destination. That would have been my first inclination too, but not anymore. Why?

a) The car seats that you rent may have been in a collision that the rental company isn't aware of.
b) The car seats that you rent are usually not properly cleaned between rentals, especially the straps!
c) The car seats that you rent are never guaranteed for make/model, so you could end up with one that you are utterly unfamiliar with and have to try to install at the rental car shop. How's that for pressure when you have a 2-year-old who wants to be anywhere but there?

The only other options are to either buy a smaller carseat for travel-only, or buy a smaller carseat once we get to Maui (and take cabs until we get one). I'm thinking that the latter option isn't going to happen, given that our flights will likely arrive in OGG at night, and that puts a lot of pressure on us to find and buy a proper car seat on Day 1.

So basically, I need to buy me an airplane-friendly, 17" wide (or less), toddler-friendly, install-friendly lightweight carseat. I looked at the Cosco Scenera, which everyone recommends because it is so light and so affordable and so safe. Unfortunately, its weight limit is 40 pounds in FF mode and less than that in RF, which means that its shelf life with us is limited. Not a good option.

I've also read about the EvenFlo carseats, which are again lighter, and also have a larger capacity in FF mode. However, they're 18.5" wide, which won't work in the narrow seats of our carrier. Plus, they use the crappiest form of the LATCH systems, and those kinds of latches are very difficult to install and remove from the vehicles we've rented.

Which leaves the Diono line. It's still heavy (20+ pounds) even though it folds up. It is also pricier than most other seats, almost enough to make me think that I should just bring the d@mn Foonf after all. Finally, it has a lower profile, which renders looking out the window a near impossibility in a car. I don't want to be stuck with a carseat that Little L hates (like the one we rented for 3 weeks in Oahu last year). She cried on virtually every drive. It made us never want to drive anywhere!

I am at a loss. What should I do? Have you traveled with a carseat? Which one would you recommend? Help, please!