Midway Airlines reported yesterday that its passenger traffic increased 129 percent in November over the same month last year. For the first 11 months of the year, the Chicago-based airline had a whopping 184 percent increase in traffic over the same period of 1980.

Although Midway operates to some of the airports whose flights have been cut back as a result of the air traffic controllers strike, the airline has not been affected greatly by it; carriers like Midway with a single flight an hour at the major airports weren't forced to cut back any flights. Its hub at Midway Airport wasn't one of the 22 airports whose flights were cut because of the strike.

A spokeswoman for the airline, which was two years old last month, said Midway has added five DC9 aircraft to its fleet this year, bringing the total to 13 airplanes. The airline's load factor jumped to 60.6 percent for the first 11 months of the year from 50 1/2 percent for the same period of 1980.

Midway earlier reported third-quarter earnings of $2.8 million compared with a loss of $70,000 in the same period last year. The July-September period was its third consecutive profitable quarter after losses in 1980.