The best answer depends on your personality, and the amount of shop space you have available.
I put the plans on a card table for most of the project, but I have a tendency to put stuff on any flat surface, so I constantly ended up with stuff on top of the plans. And, it was a bit of a PITA whenever I needed to refer to another plans page. But, if you have a card table, and the room for it, this is a quick, cheap approach.
Once I moved to the hangar, I decided it was time for another solution. I grabbed an unused easel that my wife had stashed in the basement. I cut a piece of plywood to size, propped the lower edge on the moveable supports, put a few strategically located holes in it, and used safety wire to fasten it to the easel legs. I used a one-hole paper punch to put two holes near the top edge of the plans, and used a piece of 1 x 2, carriage bolts, washers and wing nuts to fasten the plans sheets to the plywood. The holes in the 1 x 2 need to be very close to the lower edge, or the wood will cover info at the top of the plans sheets.
The easel is better than the card table for me, as I won't collect stuff on top of the plans, it is easy to move next to where I am working, and it is simple to flip to another plans sheet.