Great article but I am sure that there are numerous travel businesses that launch their affiliate courses with out 1/3 party. In fact, businesses list their amenities in Tripadvisor for instance, after which they pay commissions for each booking. TripAdvisor shares the commissions which businesses pay with other bloggers who advertise its amenities. Indeed, bloggers get only a percentage of the whole commission. Bloggers can get commissions from businesses with out using third party associates like trip marketing consultant, reserving and others.
Here is one instance and you can look for others, there are plenty.