Do you start with a good estimate of the weight you need to transport for your float trips? From the perspective of a newbie, when comparing costs for fly-out raft trips, others suggested we start with a good weight estimate for our group. Then, notes on bush plane cargo capacities (from this & other sites) helped compare the fly-out quotes based on the aircraft used by each air charter service. For example, a 1-hour flight to the put-in point, might be available for $3,000 with one service, or $2,000 with another service. Which is cheaper? Answer: depends on the weight of your load. If the first quote is for a Beaver and the second quote is for a Cessna 185, and your load, say 900 lbs, would mean two trips for the 185, then the Beaver ($3,000 x 1 trip) is cheaper than the 185 ($2,000 x 2 trips).
The need for landing in small, sometimes rough spots limits the practical size of bush aircraft in Alaska, but generally as they get larger, they carry more in fewer trips. For rafters, usually it's a 185, 206, Beaver or Goose. Awhile back, I read a discussion of air charter costs which was confusing to me because the prices did not include much info on types of aircraft or air times/distances. Here are some notes for cargo capacities of several common bush planes. Your results, the actual weight limits specified by your air charter service, may vary and should be used for your trip plans.
1. Piper Super Cub: small fuel capacity and one charter limits gear to 50#, but for non-floaters, can land on very little space like ridge tops. I think Mike Strahan once did a float in which his group landed on a ridge, then fought through brush to the river and had a good float. Packraft trip might be doable in a Super Cub.
2. Maule: approx 400#
3. Cessna 185: 700#
4. DeHavilland DHC-2 Beaver: 1,200#
5. Cessna 206: 1,200#
6. Grumman G21 Goose: approx 2,000#?: others might know better.
General descriptive info about common bush planes: