Anne, The single most important factor in selecting a design firm is the ability of those making the selection. Those who make the decisions are often uninformed, unaware, and unqualified in making the basic decisions of what design and designers can do with their precious MONEY. Most people that are new to museums think of exhibit design as "displays" which they have seen in store windows at the "mall", trade shows, Las Vegas and Disney World, which brings up the issue of the "Exhibit Designers and Producers Association". A fine organization, which I am a member, but it is dedicated more to the design/production aspect of exhibits. It is not the same as the other group which I am also a member, the "American Association of Museums" a group dedicated to the furthering of excellence in all facets of museum conception, development, and continuance. Regarding the cited much needed past experience of design firms which have done work for a "niche" museum such as an aviation museum narrowed down to W.W.II, why not limit it even further to a museum of aviation dedicated to those pilots of Polish/Italian descent whose grandmothers were married in Krakow on August 21, 1904, moved to Pennsylvania in the spring of 1912, and, after moving to Chicago in the winter of 1930 bought a used low mileage 1928 Essex two door sedan? There are probably three to four hundred design firms that have such a museum in their portfolios anxious to do still another museum of such importance--- a hard decision to make, so many slides to see and RFP's to read and ignore. My advise is to join one of the above mentioned organizations, and read, read, read some of their publications before making any basic decisions.