That could work! I'm curious what makes subscription models more attractive from your point of view. Is it just simpler to understand? It seems strictly less flexible than a pay-for-what you need model. I suppose in your example the advantage is that you can get a discount by paying for more up front which is a clear advantage for people who will take multiple trips in a year or are planning a trip far in advance.
I received a similar suggestion years ago from someone else, and it worked very well. It's effectively bigger discounts for longer & larger service plans up front. I found it effectively shifted the conversation from "How can I get a discount /beat you up on your price?" to "Ok, what is the right plan for our project"?
This is not quite like consulting/custom dev gigs, but has similar attributes. For purchases/subscriptions like yours, I've noticed that they often seem to create a tension between buying the two most likely to meet your needs - the longer higher-cost one is priced just low enough to be tempting. This probably indicates a lot of A/B testing of pricing, and decisions about whether you want to make it easier for your customers to decide, pointing customers to one plan or the other, what really drives higher purchasing levels and overall income.
They're suggesting a pricing model from the perspective of running this business instead of a pricing model from the perspective of using this service. Subscriptions are worth way more to a (tech) business than one-off purchases.