Unfortunately, other than Britax, that list doesn't include most brands sold in the UK. Seats sold in the US are required to have a specially-worded sticker on, that states that they are approved for use in aircraft. Seats sold outside the US won't have the sticker, and it is the sticker that flight crew are looking for. However, there is provision in the law for approval of non-US seats; it is just that most flight crew are not aware of what they need to look for in that case.
The US law that covers the use of carseats on aircraft is 14 CFR 121.311 (from the Code of Federal Regulations,
http://frwebgate.access.gpo.gov/cgi...E=14&PART=121&SECTION=311&YEAR=1999&TYPE=TEXT)
The pertinent section is here, at (C):
"...(B) Seats manufactured to U.S. standards on or after February 26,
1985, must bear two labels:
(1) ``This child restraint system conforms to all applicable Federal
motor vehicle safety standards''; and
(2) ``THIS RESTRAINT IS CERTIFIED FOR USE IN MOTOR VEHICLES AND
AIRCRAFT'' in red lettering;
(C) Seats that do not qualify under paragraphs (b)(2)(ii)(A) and
(b)(2)(ii)(B) of this section must bear either a label showing approval of a foreign government or a label showing that the seat was manufactured under the standards of the United Nations; (emphasis mine)
If your carseat has such a label, you may use it onboard a US commercial aircraft. By law, you cannot be prevented from using a properly labeled seat, provided you have paid a fare that entitles the child to his/her own aircraft seat. For simplicity, I suggest you print out (from the official link I posted, not from where I quoted it) a copy of the relevant section of the law, and carry it with you when you travel. Please understand that the crew will probably have to double-check on whether the printout is up to date, but having the proper citation will make that a much quicker process.
Also, just FYI, no carseat, regardless of the stickers on it, may be used onboard an aircraft in the US if the carseat lacks an integral upper-body harness. (This is in the full text of the law I cited above.)
Also, when you get your seat assignments, be sure to tell the agent that you plan to use a carseat whilst on board; there are some spots on the aircraft where carseats may not be placed, and if you are assigned one of them, the airline will have to find you different seats at the last moment, which is not fun.