Airport control towers aren’t the most obvious

subject for a compelling photographic project, but with 50 images at the National Air & Space Museum, Carolyn Russo produces an unexpectedly appealing and even poignant exhibit.

Russo ping-pongs between abstracted and straight-ahead approaches, with only her nearly monochromatic palette tying the series together.

For the novice, it’s easy enough to understand the functional importance of airport towers for air-traffic control. Less obvious is their architectural diversity, and the fact that they are surprisingly disposable. (Phoenix Sky Harbor Airport, for instance, has had five towers over the years.)

Predictably, many mid-20th century examples were burdened with an ugly, brutalist aesthetic. But with a few exceptions, such as Newark Liberty’s bland 2003 structure, the past two decades have brought an under-noticed renaissance in new and replacement towers.

One, in Edinburgh, Scotland, has smooth curves slathered in hand-installed, zinc tiles. Another, in Barcelona, takes the form of a torch (perhaps a nod to the dramatic 1992 Olympic flame lighting), while one in Bilbao was designed by Santiago Calatrava to suggest a dove. Perhaps most striking is the crescent-shaped structure in Abu Dhabi (bottom); in Russo’s portrayal, it looks too unbalanced to even stand.

Russo also documents historic and tumbledown towers, including one at a small but historically important World War I airfield in Scotland, another in Pearl Harbor that was used to direct the counterattack against Japanese planes on Dec. 7, 1941, and one at Paris’ Orly Airport that was an improbably huge tourist attraction when it opened in the early 1960s, out-drawing even the palace at Versailles.

Russo also points to the future with a photograph of the first fully remote tower, which opened in Sweden in 2014; it sends a high-definition video feed to controllers elsewhere working in a room

with a 360-degree screen.

Still, Russo is at her best when she lets her subjects devolve into pure aesthetic abstraction. The most notable of these is her photograph of a tower built in 2012 in Birmingham, England (top). Backed by blue sky and cumulus clouds, the tower’s tiles shift ever-so-gradually from pure white to pure black — a graceful depiction of a little-noticed art form in full flower.

Through Nov. 2016 at the National Air & Space Museum, Independence Ave. at 6th St., SW, Washington, DC. (202) 633-2214. Daily 10–5:30.