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- United Airlines has asked its pilots to take unpaid leave this summer and possibly into the fall.
- Across airlines, summer fliers may see disrupted flight schedules and pricier tickets.
- In June, 2.5 million passengers went through US security checkpoints.
In an early blow to summer travel, United Airlines has asked its pilots to take an unpaid leave next month, citing delayed aircraft deliveries from Boeing.
In a statement to CNBC, United confirmed the "voluntary, unpaid time off."