To be sure I understand, are you saying you want the user only to be able to select from
(optional All of these 3)
Or do you want them to have the option for All?
All (including Aircrafts)
If Set #1, then you could get to that just by duplicating your dimension field and adding both to the filter.
You can filter the Copy to only include Cars, Buses and Rail (and not Aircrafts). Then you can expose the non-copy dimension as a filter and choose to show relevant values only. You can also choose whether or not to include the "All" Option, which would still exclude Aircrafts.
If Set #2, where you actually want to "blend" Aircrafts into a non-selectable dimension, but you do want the data included when ALL is selected, you could create a parameter and calculated field combination.
1) Make your parameter a list with (All), Cars, Buses, Rail as the members.
2) Create a calculated field as:
IF [parameter] = '(All)' THEN 'Show'
ELSEIF [parameter] = [dimension] THEN 'Show'
3) add your calculated field to the filter and include only 'Show.'
4) expose your parameter so the user can choose which items to show--Here, All will still allow Aircrafts data to be viewed