Traveling CPAP Machine

I am shopping for one before a long trip

If you get one, it's a good idea to use it at home for two weeks before going on a long trip.

Might be nice to know what you are currently using. If you happen to be using one of the specialty machines you might end up getting the wrong type of machine just because you want tiny and it be a total waste of money.

So what machine are you currently using?
What pressures are you using now?
Are you using added humidity...if so how much and how would you do without humidity? Might try going without at home to see what happens to your nose if it doesn't get enough added moisture.
Are you super sensitive to noise?

Look for a used S8 Auto. Perfect travel machine without the humidifier; small with self contained power supply = no power brick to deal with.

If it's a one trick pony, I would recommend used (and take suggestions from these other folks about specific machines). A Resmed S9 or Respironics 560 are great choices if you leave the humidifier behind. They are small. However, they do have a power brick. For Domestic and many European flights, cpap machine is not considered a carry on as it is a medical device.

The Phillis Respironics 560 is the machine I use for traveling as it seems to give me the greatest number of options: use with humidifier or without, with power (yes it then does have a power brick) and without power with only a short cord between it and a small lithium battery ( it is 12v as opposed to the ResMed 24 v) and batteries are easy to find. I use a PowerAdd 32,000, available from Amazon. I can get 3 9+hr nights from a full charge and then have the option of recharging from 110, 12v, or solar.