Maybe sixty missions were too many for the men to fly, Colonel Cathcart reasoned, if Yossarian objected to flying them, but he then remembered that forcing his men to fly more missions than everyone else was the most tangible achievement he had going for him.
There are no more uses of "tangible" in the book.
Show samples from other sources
They set tangible goals.
The performance goal should be expressed as a tangible, measurable objective, against which actual achievement can be compared.