Yep - plywood works fine (as does a card table at one end of the table).

The large tablecloth covers all!

I would do the plywood but round the corners slightly just for safety/comfort.

The plywood sounds like great idea, was about to order "table pad extender" for same reason, can anyone tell me how much larger I can make the plywood?? I was going to make my table a little wider, and a total of 12 inches for the length... Can I do the same with plywood??? Thanks!!

I think you can make the plywood as big as you need it to be and will fit. Don't forget to protect your table before putting the plywood on top.

Just throwing this out there, but for the ptice of plywood (doesn't that just come in 4x8 sheets?) you may be able to pick up a large enough table on Craigslist and sell it afterwards. :)

My mom & dad always did plywood. My Dad had it in two pieces (so it could be stored) and somehow connected them in the middle before putting it on the table.

I think that the plywood is a great idea for now. However, just another thought: I had the same dilemma years ago. My dining room table could extend to hold another leaf but I didn't have it (bought table at an auction). I paid a carpenter $100 to build me a leaf with a matching finish. You cannot tell that it hasn't ALWAYS been a part of the table.

Thank you everyone. I didn't even think of plywood! What a great idea!
Joanie, that's definitely a budget friendly option as well. My table will hold one more leaf, but it's from a friend (free!) and he only had one. Hmmm. Everything on cL right now is $250+ so that won't work.

I used the plywood overlay when newly married and having the whole fam for dinner. I covered the plywood in heavy-duty felt that I pulled to the underside and stapled down. It made the edges look softer when the tablecloth was draped over them. And it kept it from sounding like a gym floor when glasses or bowls were set down on the table.

IIRC, to protect the table top, we covered the table with a blanket and duct taped the excess to the underside of the table. Then laid the felt covered plywood on top.

Linens and Things has some fairly inexpensive, large tablecloths

We have a simple piece of rectangular plywood ( the same thickness and size as our other leaves )that we use as the last insert when we need to seat 14 instead of the 12 that would fit with the two existing matching leaves.This is a LOT easier that using larger plywood panels that go over the tabletop, and stores easily with the other leaves when not being used. We always use a tablecloth for such large dinners anyhow, and you cannot tell the difference.

If you only need 12 inches, why not go to lumber mill & buy a pine board that size, will be nicer than plywood. Get the length you need to fit the table. Having been in the antique business for 30 yrs. we have made many leaves for tables, not unusual to have the leaves missing from tables we purchased for resale. Pine will be very easy for you to stain to match your table if you choose to do that, then you could use the table without a cloth if you want to.