Eastern Air Lines lost $67.4 million during a fourth quarter fraught with fare wars, but still managed to turn its first yearly profit of the 1980s, the Miami-based carrier reported. An earnings statement said Eastern reported a net profit of $6.31 million during 1985, a $44.2-million improvement over its 1984 performance. The last time the company had a yearly profit was 1979, when it made about $50 million. From 1979 through 1984, Eastern lost $379.8 million. Eastern President Frank Borman attributed a poor fourth-quarter showing to a sharp decrease in passenger yield on industry-wide fare cuts during the period, the statement said.