These days, wings over Miami are likely to mean airfreight

To earlier generations, the words ''freight shipments'' evoked images of long trains and cargo-carrying steamships. But in Florida today, as in much of the rest of the world, cargo more and more often moves by air.

Florida's air cargo industry has fared relatively well through the recession. This year, tonnage is back up again and air cargo sales are on the rise at Florida's three busiest airports, in Miami, Orlando, and Tampa.

Florida and aviation appear to be made for each other. The state is far enough from major population centers to make a good many tourists feel flying is the best way to get there. And the state is big enough to justify considerable intrastate aviation.

Airfreight flies in and out not only in cargo planes but in the underbellies of passenger jets. Florida's lush climate yields produce and perishables like tropical fish and cut flowers best shipped by air.

The products of Florida's electronics companies - light in weight but high in value - are another natural for airfreight.

Miami International Airport is the world's No. 5 cargo field, after Kennedy in New York, Los Angeles International, O'Hare in Chicago, and Frankfurt, West Germany. At its current rate of growth, it is expected to jump ahead of Chicago and Frankfurt by 1985 to claim the No. 3 spot.

The Miami area is not a particularly big originator of airfreight. A major portion of the air cargo activity at Miami International is transshipments - from one airline to another, or from jet to truck. And much of the cargo traffic is between Miami and Latin America.

The International Airport at Miami has two big advantages to help it garner the Latin American air cargo trade. One is natural - geographic proximity. The other is one that Miami has carefully fabricated: its 13,000-foot runways, which permit large jets to take off with a full payload of cargo.

Preliminary figures for 1982 indicate that Miami will post a second year in a row with airfreight sales of over $3 billion. The tonnage for 1982 will probably post a small drop of around 3 percent over the previous year: 219,000 tons in 1981, against 210,000 last year. The loss is attributed to weakness in Latin America generally.

What sort of things are shipped by air through Miami to Latin America? Some of the items, especially in better times, are surprisingly bulky and heavy: televisions sets, computers and office equipment, automobiles and jeeps, even oil-drilling gear.

Interestingly, the busiest air cargo handler in Florida is not an all-cargo airline such as Emery or Flying Tigers but Miami-based Eastern, an airline better known for its passenger service.

Jerry Schorr, Eastern's vice-president for cargo sales, reports sales are up. ''We experienced an increase in sales last year and we're already seeing an increase in the first part of this year,'' Mr. Schorr says.