I thought this "organization" was conceived to "rescue" dogs and move them to an area where they could find new homes. Maybe it is the skeptic in me but when I see a single dog going to a home I wonder if this is a rescue mission or someone requesting taxi service to save themselves a few dollars to ship the dog from one place to another.
I've come late to this post but I want to throw in my 2 cents from the perpective of a rescue.
As I understood at the time, PNP started as a bulletin board type of system for rescue orgs and pilots to connect and team up to move dogs that are already in rescue, or are ready to be accepted by rescue. The dogs typically spend 3 weeks in foster care while they are evaluated as to temperament, personality, basic obedience, training requirements, etc, while the rescue is also evaluating prospective adopters. I'd say this is true for 80-85% of posts requesting assistance. The appropriate new home or even the best temp foster isn't necessarily in the same city (or state) as the animal.
Sometimes, individuals operate similarly to rescues but lack a volunteer network to assist with transport, trips to the vet, and foster care, so are working on their own in an attempt to help a creature however they can, and they post requests too.
In some cases, shelters have volunteers or community "friends" willing to help rehome pets that are unwanted in their own area, including lining up transportation by whatever means. I'm thrilled that shelters, who until recently had no idea about transport (via any means) or how rescues function, have begun to turn to pilot themselves.
I network with other rescue orgs and shelters throughout the country. I rescue one breed from all of the US, and adopt TO homes in all of the US. This is a less common breed so I am usually routing long flights. I wouldn't combine adult dogs on a flight unless they'd known each other for some time beforehand; pilots have enough to do without listening to two dogs grouching at each other. And because they're fairly large dogs, there isn't room for two crates, although I do browse posts for other dogs going my way in case they'll fit in the airplanes and the pilots are willing.
All these factors and more culminate in the stage that you see-- the flight requests. If pilots did what rescues do, I don't think they'd have much flying time available, as rescue is usually a 24/7 effort in vetting, evaluating, working with our fosters, training and transporting. Arranging transportation, by whichever means or combinations, is and always has consumed the bulk of our time; PNP hasn't changed that but it DOES give us more options. It also substantially increases the odds that dogs in need get where they most need to go.
Yes, there are requests here from people looking for taxi rides, as you put it. Some pilots care very much about a poster's motives, as do some rescues. There are hoarders adding to their collections by getting dogs from all over the country that they wouldn't otherwise have access to. Pilots hear from breeders wanting delivery of their sold puppies, puppy buyers looking for a free ride, and people who are moving but didn't make arrangements to take their pets with them. We rescues are contacted by non-member pilots, people posing as pilots, and people offering to transport for a fee. I don't like that stuff but it isn't totally unexpected in a system like this. In the end, it comes down to deciding which requests pilots want to answer depending on their personal thoughts about each case.
I wish you many enjoyable trips!