There seems to be a minor point of confusion here. Some fly plaids are made with a built in strap & buckle to fasten at the waist. Some are not.

These are essentially the same item, just made in two different styles. When worn, they will hang a bit differently, but other than that, there is no difference, and it does not really affect the formality of the ensemble at all.

Some people seemed to be treating these as two separate types of plaids, but they are essentially both the same.

As to the appropriateness of wearing the fly plaid, I actually think this is a bit fluid -- in other words, the fashion may be changing -- and depends a lot upon the country you may live in.

Most of the people I talk to from the UK would reserve the plaid for "white tie" affairs, worn with some type of close-fitting doublet, like the Montrose or Sherrifmuir. They would not consider it part of "black tie" attire and would never wear it with the Prince Charlie.

A lot of people I encounter here in the States still consider the fly plaid part of formal affair, but (and this may just be the circles I run in!) don't make the same distinction between "white-tie" and "black-tie" and wear the fly plaid with their Prince Charlie. It certainly does not look bad. And I dare say that most people who wear the fly plaid in the US wear it in this manner.

So I think it really boils down to your personal sense of style and what is generally considered appropriate in your region.

What is generally considered unappropriate everywhere is the use of the fly plaid as part of a casual ensemble. You can literally see anything being worn at many of the Highland Games in America (I once saw someone wearing his Prince Charlie & vest with a t-shirt, for goodness' sake! I saw someone else wearing bedroom slippers with his kilt...). I will occasionally see someone wearing a formal fly plaid with a sweater, or even worse, a t-shirt! It's not uncommon to find people wearing it with a "Jacobite" style shirt.

I think a lot of this is due to neophytes jumping in head first and purchasing a lot of accessories, thinking that since they are all "Scottish" they must all go together, without considering that there are different styles, different levels of formality, and you cannot always mix them.

If one is looking for a more casual form of plaid, the "blanket" style that many have mentioned from Thompson's book (So You're Going to Wear the Kilt) is very traditional. Essentially this is a blanket -- maybe 2 to 4 yards of your tartan, fringed at two ends, folded up and draped over yoru shoulder, like you were carrying a blanker on picnic. Problem with this is that for most of the outdoor festivals in the summer months (when people in the US typically wear their kilts) you don't really want to carry a large woolen blanker around all day.

Another option that I have seen is a modified plaid that is made to resemble the upper portion of a great kilt, but is not so fancy as the fly plaid.

Take one yard of double width tartan (to match your kilt), which would be 36" by 54" (If you are a larger gentleman, you may want more than this, say 1.5 yards, so it would be more like 54" x 54"). Hem the two cut ends (there is no fringe on this style). On one of the selvedge ends, sew a small loop in the center (this can be cloth, bias tape, cord, whatever). On the other selvedge end, put in a draw string.

After you put on your kilt (but before donning your jacket) fasten the plaid at the waist with the drawstring (it is not essential that it come all the way round to the front). Then fasten it with the liitle loop you've sewn on at your shoulder with a simple brooch or pin.

The cloth should drape in such a way that it looks reasonably like the upper portion of the great kilt. I've seen this worn with a tweed Argyle jacket and a plain brooch (not the fancy formal plaid brooch with large gem) and it has actually looked quite nice. The plaid did not look too formal for the outfit in the least.

So if one were looking for a version of the fly plaid to wear for daywear, this is what I would recommend. But I'd still stress that you really need some kind of jacket to pull this off -- wearing the plaid with just a shirt would still look out of place in my opinion.

M