From a technical perspective, my opinion as a frontend dev is that this isn't a very hard thing to do. Probably a few hours of work for a basic version with average CO2e values. If you need to look up the precise value by plane type, occupancy, distance, speed, etc. it will get trickier, but probably the end result won't be all that different.

If you want to see a basic prototype, I can volunteer to help you make one in the next week or two, especially if you can provide the numbers ahead of time.

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But from an environmental perspective, I think the bigger issue here is that orchestras probably don't have a lot of practical alternatives. Who would the site be targeted to? What do you want them to do differently after having seen it? It's one thing for a single person to use a carbon footprint calculator to see which of their habits they can change... but that's one person (or maybe just their immediate family). But when you have to send an entire group of 30+ people across countries or continents, the problem becomes a lot harder. Organizing multiple carpools means also arranging food and lodging along the way, which can quickly get very expensive. Traveling by train is largely dependent on the available routing and speed (better in Europe and Asia, terrible and totally impractical in the US). Either option turns a simple several-hour flight into a multi-day affair, which means all the people have to further coordinate the trip with their families' schedules. A bus would come somewhere in between the two, especially if you can charter a private one for the orchestra, but you still have to account for several days of food and lodging.

Liabilities and insurance will probably go up too, since there are so many more unknown variables along the way (road closures, traffic, accidents, breakdowns). Per passenger mile, flying is probably still the most reliable & safest way to get groups around. If a plane malfunctions, the airline will usually get you there within a few hours, either by getting another plane in or moving people to different airports/airlines. If your chartered bus breaks down along the way, it will take a long time for another one to drive over to it and take over. If your train malfunctions or the track is busy or snowed in or whatever (as is often the case across the continental US), it can be a multi-hour delay or sometimes even overnight (it's really bad here).

And at the end of the day, it wouldn't necessarily even save THAT much CO2e, depending on the specific routes taken and how full each vehicle is. Air travel is much maligned in the public mind, but in reality it's not really always so bad from a climate standpoint. Here's a random example (see PDF page 15): https://railroads.dot.gov/sites/fra.dot.gov/files/2022-12/CO...... the plane is often better than a single-driver car, for example, and only a little more than a train.

It would take a herculean effort to change the travel patterns of orchestras for such minor savings. Probably easier to just get them to donate a certain % of the airfare to verified carbon offsets, as many airlines and rental companies already do. There's examples of orchestras doing this too, as in https://symphony.org/features/touring-and-the-climate-smart-...

Bang for the buck, that's more likely to actually be climate-positive (compared to all the additional costs of food, lodging, insurance, not to mention rescues if anything doesn't go according to plan along the way)... those dollars can be more efficiently invested in climate projects (existing offsets or new plantings) rather than spent on restaurants and hotels. Unless the orchestra was going to charter its own private plane (do they do that?), that flight is going to happen anyway, just with fewer passengers (making its emissions even worse, since now you have to add the flight on TOP of what the orchestra is emitting on the roads).