Spring break travelers heading to airports during the ongoing partial U.S. government shutdown should brace for potential delays, with experts warning security lines are already stretching for hours at some airports.

Passengers across the country are reporting longer Transportation Security Administration (TSA) wait times, flight delays and crowded terminals, and security lines at some airports are topping three hours, according to Eric Napoli, chief legal officer at travel company AirHelp.

Airport security lines in Austin, Texas, stretched out the door early Friday, with passengers waiting hours to board flights.

"For passengers that did not factor in the possibility of longer lines, many are missing their flights as a result," Napoli told FOX Business.

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The disruptions come as more than 300 TSA officers have left the agency since the Department of Homeland Security (DHS) shutdown began. Unscheduled absences — or callouts — have also climbed to roughly 6% nationwide, a TSA official previously confirmed to Fox News Digital.

"When critical aviation personnel, particularly TSA officers, are working without pay, the result is staffing shortages and operational strain across airports throughout the country," Napoli told FOX Business.

Global Entry processing, which had been paused earlier during the shutdown, resumed last Wednesday, a move Napoli said could help ease congestion by shifting some travelers out of standard security lines.

Napoli advises travelers to plan ahead to avoid disruptions, including arriving earlier than usual and booking early-morning flights, which are less likely to be affected by cascading delays throughout the day.

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Passengers should also pack essential items in carry-on bags in case of baggage delays or overnight disruptions.

Napoli urged travelers to understand their rights if flights are canceled or significantly delayed.

"If the airline informs that passenger that their flight is canceled or that there is a new schedule that makes the flight significantly delayed, the passenger is entitled to reject the new schedule, decide not to take the flight and obtain a full cash refund," Napoli said.

For baggage issues on domestic flights, airlines must reimburse reasonable expenses up to $3,800 per passenger under federal regulations, he added.

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Travel insurance and certain credit cards may also provide coverage for delays, missed connections or lost luggage.

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"The best prepared passenger is one that is well-informed on their rights in various flight scenarios and when they can pursue compensation," Napoli said.

Fox News Digital's Louis Casiano and Ashley DiMella contributed to this report.