Should the public have to pay for public transport?

So, me and my friend were having a debate earlier today, and I thought I’d ask what you guys think about it.

My friend said that people shouldn’t have to pay for public transport, like trains, trams, planes, buses etc. She thought this because public transport helps save the planet by releasing less emissions and things that are bad. She said it should be free to encourage people to save the planet, since more people in one vehicle means less emissions and stuff.

I understand where’s she’s coming from, but if people didn’t have to pay, bus drivers and people like that wouldn’t get paid, which means people won’t want those jobs, and it’ll just end badly.

What do you guys think?

No rude comments below please, and no arguing. I’d like this to be completely civil x