In 2020 I was taken by helicopter to a hospital and i am still paying this off. can i deduct what i paid last year for this?

That would be a medical expense which is allowed as an itemized deduction, so you can enter the amount you paid during the year, along with other medical expenses,  in the Medical section, then Medical Expenses, under Deductions and Credits. However, it may not benefit you as the medical expenses are only deductible to the extent they exceed 7.5% or your adjusted gross income. Also, you need to have enough in total itemized deductions for it to be more than your standard deduction for the deductions to benefit you.

Possibly.  Medical expenses are deductible when you pay the provider.  If you are paying the helicopter ambulance company, then whatever you paid in 2024 would be deductible in 2024 (subject to the usual limitations).  However, if you paid the provider previously with a loan or credit card, and are now paying off the loan, that is not deductible now, but would have been deductible when you paid the provider.