The move was made in an effort to tame overcrowding in the airspace and delays, the airline said.
It impacts domestic departures only, which comprise approximately 12% of flights for United, and will go into effect for domestic flights July 1.
"This schedule action will help minimize excessive delays and improve on-time performance," said United CEO Scott Kirby in a statement, "not only for our customers, but for everyone flying through Newark."
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