Most of the subsidy is in the form of tax reductions, a little is in cash like payments (e.g. increased car allowance). But what does it matter? The distinction is purely arbitrary. If the government said "there will be no tax reductions, you get an equivalent cash payment instead", the end financial situation for both you and for the government is exactly the same.

If I sell you a donut for $3 and then give you $1 back, or I sell you a donut for $2, is there any meaningful difference?

Investopedia defines subsidy as

"A subsidy is a benefit given by the government to groups or individuals usually in the form of a cash payment or tax reduction."