What are your tips for successful pup's first plane ride?

Great Topic! I'd suggest start by contacting the airline and finding out exactly what's required. I've been told some carriers (maybe United was one) no longer require pet carriers for dogs flying in the cabin. If there's any possibility you'll need a carrier, you'd want to ask them what are maximum dimensions, as that varies with each airline carrier. Also, confirm if you need to "book a place for the dog" because some airlines restrict each flight to a maximum number of pets, even for dogs that have to ride in a carrier in the foot well. I understand from other ESA pet owners that they don't pay for additional tickets, but I'd suggest confirming that too to prevent a surprise confrontation. They will also likely tell you the documentation requirement: proof from city or county licensing and vet with immunization record to show at gate, which has a specific time window that it must be generated prior to flight (X number of days). That leads to of course setting up the vet appt. and getting printout of whatever you may need as well as any sedative. The vet will provide the instructions regarding dosage, fasting prior & throughout flight, and may recommend a trial dose at home days before takeoff. If you're not familiar with a connecting airport you'd travel through, contact them to see a layout of relief areas and relationship to security checkpoints and gates. It can be beyond stressful to have to dash through an unfamiliar airport to outside, where there is a designated pet relief area, then processed again through security, and head back to gate. Some, but not all, airports have a pet relief station inside - which may also figure into your flight plan.