This past fall we used Phoenix Travel of Fairfield twice, including 6 people on one of the trips. Ariana is the owner.
Because we are from just outside New Haven, they charged a little more to pick us up. I think it was $220 each way plus a tip.
For me, it is well worth not having the stress of going down in traffic or worrying about the trip home (ours was 9 at night flight back). On one of the return, our scheduled driver had an accident but Ariana quickly arranged for a back up.
The other option is try to locate a Lyft or Uber driver to moonlight. If you know a driver from one, they can probably give a referral. (or ask Ariana if she knows someone around Hartford)
You probably know this but leave plenty early - better to be 2 hours early than 10 minutes late.
Enjoy your trip.