I would check with the airline... but within the United States it (your medicine) appears to fall into one of the items which are exempt from the hazmat regs... you should be able to transport your aerosol medicine without any problems as long as you're not bringing lots of it... (see below), you might have problems outside the US... also for customs purposes bring a copy of the prescription so that the customs/agriculture inspectors don't hassle you:
(4) The following hazardous materials when carried by a passenger or crewmember for personal use in conformance with the following conditions:
(i) non-radioactive medicinal and toilet articles (including aerosols) may be carried in checked or carry-on baggage;
(ii) one self-defense spray (see 171.8 of this subchapter), not exceeding 118ml (4 fluid ounces) by volume, that incorporates a positive means to prevent accidental discharge may be carried in checked baggage only;
(iii) other aerosols in Division 2.2 with no subsidiary risk may be carried in checked baggage only; and
(iv) the aggregate quantity of hazardous materials carried by the person may not exceed 2 kg (70 ounces) by mass or 2 liters (68 fluid ounce) by volume and the capacity of each container may not exceed 0.5kg (18 ounces by mass) or 470ml (18 fluid ounces) by volume.
As for propane (hazard class 2.1 item), it's forbidden aboard any aircraft carrying passengers, although there is an exception.
Woodreau / KMVL
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.