NEW YORK (TheStreet) -- Shares of Delta Air Lines Inc. (DAL) - Get Report are gaining by 1.70% to $44.84 in mid-afternoon trading on Friday, as airline stocks are getting a boost from the declining price of oil. Fuel can be an airline's largest expense.

Crude oil (WTI) is slumping by 3.07% to $49.85 per barrel and Brent crude is falling by 2.50% to $57.71 per barrel this afternoon, according to the index provided by CNBC.com.

Oil prices are in the red today as concerns ease regarding the possibility of supply disruptions resulting from Saudi Arabia's airstrikes against rebels fighting in Yemen. On Thursday the conflict saw oil prices rally and airline stocks fell.

Between June 2014 and January 2015 oil prices dropped by more than 50% on global supply glut concerns. In November OPEC announced it had no intention of cutting its production rate, sending prices down further. In February oil prices steadied and have gone back and forth between the red and green in March.

Separately, TheStreet Ratings team rates DELTA AIR LINES INC as a Buy with a ratings score of B-. TheStreet Ratings Team has this to say about their recommendation:

"We rate DELTA AIR LINES INC (DAL) a BUY. This is driven by a few notable strengths, which we believe should have a greater impact than any weaknesses, and should give investors a better performance opportunity than most stocks we cover. The company's strengths can be seen in multiple areas, such as its revenue growth and solid stock price performance. We feel these strengths outweigh the fact that the company has had sub par growth in net income."

Highlights from the analysis by TheStreet Ratings Team goes as follows:

• DAL's revenue growth trails the industry average of 22.1%. Since the same quarter one year prior, revenues slightly increased by 6.3%. This growth in revenue does not appear to have trickled down to the company's bottom line, displayed by a decline in earnings per share.
• Compared to its closing price of one year ago, DAL's share price has jumped by 40.11%, exceeding the performance of the broader market during that same time frame. Looking ahead, the stock's sharp rise over the last year has already helped drive it to a level which is relatively expensive compared to the rest of its industry. We feel, however, that other strengths this company displays justify these higher price levels.
• DELTA AIR LINES INC has experienced a steep decline in earnings per share in the most recent quarter in comparison to its performance from the same quarter a year ago. The company has suffered a declining pattern of earnings per share over the past two years. However, we anticipate this trend to reverse over the coming year. During the past fiscal year, DELTA AIR LINES INC reported lower earnings of $0.75 versus $12.29 in the prior year. This year, the market expects an improvement in earnings ($4.84 versus $0.75).
• Even though the current debt-to-equity ratio is 1.11, it is still below the industry average, suggesting that this level of debt is acceptable within the Airlines industry. Even though the debt-to-equity ratio shows mixed results, the company's quick ratio of 0.39 is very low and demonstrates very weak liquidity.
• Return on equity has greatly decreased when compared to its ROE from the same quarter one year prior. This is a signal of major weakness within the corporation. In comparison to the other companies in the Airlines industry and the overall market, DELTA AIR LINES INC's return on equity is significantly below that of the industry average and is below that of the S&P 500.
• You can view the full analysis from the report here: DAL Ratings Report