Airline service quality is hard to quantify, but the U.S. Department of Transportation keeps certain statistical measures on the 20 biggest carriers. Here's how Delta and Northwest stacked up for 2007:

ON-TIME PERFORMANCE (percentage of flights arriving within 15 minutes of schedule)
Rate and ranking
• Delta: 76.9, 5th
• Northwest: 69.6, 13th
• Industry average: 73.4

BAGGAGE HANDLING (mishandled baggage reports per 1,000 passengers)
Rate and ranking
• Delta: 7.60, 12th
• Northwest: 5.01, 4th
• Industry average: 7.03

INVOLUNTARY BUMPING (number per 10,000 passengers)
Rate and ranking
• Delta:2.47, 16th
• Northwest: 0.83, 8th
• Industry average: 1.12

COMPLAINTS TO DOT (per 100,000 boardings)
Rate and ranking
• Delta: 1.81, 18th
• Northwest: 1.43, 15th
• Industry average: 1.37

Note: Figures are for mainline operations and do not include commuter affiliates.