Zipcar lands in Chicago airports

• Zipcar announces it will start its car-sharing service at Chicago's O'Hare and Midway airports.
• The subsidiary of Avis Budget (CAR -0.4%) is now in 26 airports globally.
• What to watch: The acquisition of Zipcar by Avis drew some criticism because of the hard-to-ignore fact that the car-sharing service could rep a trade-down for some consumers. After Avis promised $50M-$70M to $70M in deal synergies, it might be on the hot seat to deliver.