Yes, bait it with meat. I've been so desperate to keep yellow jackets away from our (dog club's) annual June picnic that I've even bought...bacon...to bait the trap with (non-pork-eating household). My home-made traps caught over four dozen yellow jackets in about 3 hours.
1-gallon milk jug, preferably with cap
Scissors or utility knife
dishwashing liquid (I used Dawn)
1) Cut a pair of matching holes
on opposite sides of the jug towards its top. (Read these instrux all the way through to get an idea of a good size for the holes.) Squirt a bit of Dawn into the bottom of the jug, avoiding the sides, and follow it with water. If some Dawn did get onto the sides, strategically aim the water there. You're going for a solution of Dawn + water but not the suds, so pour the water slowly.
2) Cut a slice of bacon into three or so pieces
. Small is good. Thread string through each piece of bacon such that you can hang the string from the stick inside the jug, but the bacon won't touch the Dawn + water. THIS IS CRUCIAL.
3) Carefully hang the jug away from the reach of children
or curious cats or boisterous dogs. Use more of that string through the jug's handle and secure the handle to...a branch, a crossbeam, an angle reinforcer. Reasonably near where you've observed these yellow demons in flight.
4) How it works:
Yellow jackets are attracted to the meat. We couldn't keep them away with sticks from a bucket of fried chicken at the picnic the year before I made these traps.
But the fruit salad was virtually untouched.
Bait the traps with meat.
Once the yellow jackets eat the meat, their instinct is to drop down and then fly away. AHA! That dropdown is what you're waiting for: that's when they contact the Dawn + water. They can't get back out. (Keep the cap ON the jug; don't give them additional means of escape.)
The bottom of one jug had so many yellow jackets that it was pretty much covered with them.
People and dogs were greatly relieved.
Sunset Zone 17, USDA Zone 9