Yesterday, I was heading to my local leisure centre for puppy class (which is more like socialization class than anything).  I was running late, so i decided to place him in the car and zip down.  He now weighs 28 kg and is not fond of the car at all.  Granted, i've driven before with him, but that was around the 18kg to 20kg mark.. and i'm afraid i just can't lift him anymore.  I've tried tossing in his kong, treats.... and even the Tom Hanks trick of entering in first (Turner & Hooch).  Needless to say, I was the only in the car with my dog planting firmly on the pavement.  I didnt want to pull at him, or turn into a tug of war. So I gave up and walked.  (Turns out class started 10 minutes late).

I probably should have started this early, but i was very protective of not scaring him off the car.... (both the breeder and i had to literraly lift him in his bed to place in the people carrier on his first ride). 

Any suggestions would be appreciated.  Thanks.

Have you tried luring him in with some incredibly tasty titbit??  Not just regular treats but, say, smoked fish or something really stinky?

Yes.  He doesnt do dry treats, but loves raw chicken and lamb (the prepackaged frozen ones.  I tried guiding him in with it, even put it on the car seat and floors.  Car seat didnt work, he put his head in and got it, and the floors were a bit deep for him to notice.  See the problem is best descibed this way:

If i hold the leash and go to the car first, he looks the other way, or plants himself firmly against the pull of the leash.  Sometimes lying down.  Any treat can be missed this way.

If i keep his attention on the treat as we get closer to the car door, again... pulls back or lays down flat..

Ok, well I would try this:

Have a really energetic game of tuggy with him right by the car (with car door open).  Get him really worked up and into the game and be really excited yourself.  Sometimes chuck the tuggy away for him to get and continue the game.  Then just chuck it into the car, and see if he'll go in to get it.

Maybe just taking his mind off the car and onto the tuggy will help. 

Mine are liftable but normally don't jump willingly until around 12 months or so, and then there's no keeping them out! :)
If I HAD to get a big dog into a car, (in case of emebergency) I would lift the front 2 legs and tie the lead into something in the car so that he can't jump out again.  Then I would lift the back to legs, sit in the car with the dog and make a big fuss, give a special treat etc.
Apart from that I'd get him into the car at every opportunity, however short the journey, with a treat and lots of praise every time.

Can you get a car happy doggy friend to go with you?  Put the other dog in first.  Maybe feed the other dog in your car.  Once you do manage to get him in, without the doggy friend, feed him his meal for the day (or one of) in the car?  You don't want two dogs fighting over food in your car and you may need the other dog's owner to keep the two from playing in your car and wrecking it.

Just thinking out loud here but the other dog bit works for my sister's BC.

Mine hated the car as he's prone to getting sick. I spent a week just getting him in without moving the car before each walk. I started by opening both back doors and with a long lead went straight through the car with a tasty treat. I think having the other door open made it look like he had a way out so he was more willing to get in. When he hopped in he got a treat - it took about 5 minutes of a most ridiculous display on my part with treats and toys but the neighbors are used to me. Then I let him come out the other door and he got to go for his walk. Then when he was happy with that I got in with the door closed. He hopped in with me, got a treat, we both got out and we went for our walk. When we were ready to drive off I used the proximity of his training club to my advantage as he loves going. I used to walk but started driving so after a short 5 minute drive he gets to go somewhere nice. Same for the local beach etc.

Jetstone's friendly dog trick worked for him once we got to the training club. Once a dog was in back I couldn't keep him out but then he LOVES other dogs.