I'm here to offer insight on deleting inactive vehicles and to provide assistance you can consider.
The ability to delete them so they won't appear on the Tax Summary report is unavailable. Please note the following when inactivating a vehicle:
If your vehicle is currently set as the primary, you won't be able to designate it as inactive. To do so, you'll need to assign a different vehicle as the primary vehicle before making the current one inactive.
Even after you mark a vehicle as inactive, your existing trips will remain associated with that vehicle.
You can still export trips for inactive vehicles whenever you need to.
While the option to remove specific transactions or vehicles from the report is unavailable, you can consider exporting your report to Excel so you can remove a vehicle when necessary.
Additionally, I recommend exploring these articles that provide valuable information and guidance on tracking and managing your business miles: