Delta Air Lines ( DAL ) fell Wednesday for the second day in a row in the wake of a credit downgrade by Fitch Ratings.

Recently, shares were down 33 cents, or 3.9%, to $8.08, following a 1.7% loss Tuesday. Shares hit a 52-week closing low of $7.12 on March 24.

The ratings agency cut Delta's credit rating on Tuesday because of concerns over the airline's high labor costs.

Delta management is trying to renegotiate a contract with its pilots union, among other labor concessions, as part of a broad cost-cutting effort.

Analysts at two Wall Street firms have downgraded the stock since the beginning of the year.

The airline recently increased its estimated first-quarter loss to $400 million, citing higher fuel prices and "continued pressure on passenger revenue," and said the situation further illustrates its "critical need to reduce costs to a competitive level for the long term."

Previously, the Atlanta-based carrier had forecast a loss of $300 million to $350 million. The current consensus forecast of analysts polled by Thomson First Call is a loss of $334.1 million. Analysts also expect Delta to lose $2.95 a share, compared with a loss of $3.51 a share in the year-ago period.

Delta reports first-quarter earnings April 14.