Summary
- Domestic to domestic flights rarely require security checks.
- The US & the EU have similar security standards for domestic/international connecting flights.
- International to international flights almost always necessitate security checks as standards can vary across countries.
Transiting can be a hassle for travelers and additional security screening can make the process more troublesome, having to take out personal belongings and comply with the many security regulations such as the liquid rules. For airlines, it can increase minimum connection time (MCT) and comprise efficiency. However, security screening is not always needed when transferring between two flights, and we will be breaking down the general factors that will decide whether a security check is needed or not during transit.
Airports and aviation authorities' ultimate goal is to ensure the security of flights, and to do so a set of standards needs to be met. Therefore, most rules are based on whether the incoming flight satisfies the security requirements of the airport or the country. In addition, some airports have rules that are set based on logistics setup.
Photo: Elliott Cowand Jr | Shutterstock
Security depends on the type of transfer
Domestic to domestic
Security checks are very rarely needed when connecting from a domestic flight to another as the same security standards are typically enforced across a country. This also includes connecting between two flights within the Schengen zone where the same regulations apply and no customs are needed. Travelers simply need to get to their next gate to board the flight.
However, there are a few exceptions around the world, one being in Australia, where different screening rules apply to planes under 30 seats and some additional screenings are needed.
Domestic to International
It is also typically not necessary to go through security for such a journey. In the EU and the US, the same security standards are enforced for both domestic and international flights, therefore allowing travelers to connect without screenings. In the EU context, this refers to a Schengen to non-Schengen transfer.
Photo: Jim Lambert | Shutterstock
International to domestic
In most cases, security checks will be conducted when connecting from an internation flight. Most airports, such as London Heathrow (LHR), enforce the rule for travelers connecting from all international flights. In the US, all passengers arriving internationally, regardless of final destinations, need to go through immigration, which means security for boarding the next flight.
Many airports, such as Amsterdam Schiphol, have different rules depending on the flights' country of origin. Amsterdam has a system of 'clean' and 'dirty' destinations, where 'clean' means no additional screening is needed when transiting, including flights from the US and the UK, while 'dirty' means the travelers need to pass through a security check before boarding the next flight. Similar rules are present in Frankfurt and Munich, where not all travelers arriving from international or non-Schengen destinations need to clear security.
Photo: Amsterdam Schiphol Airport
International to international
Security checks are almost always required when transiting between two international flights. As the standards vary across countries and regions, most airports screen all passengers on such an itinerary, regardless of the origins of flights.
In the US, the TSA sets the same security rules for every airport and, therefore, it is fairly easy to deduce whether one needs to go through a security check when transferring. Note that flights that use CBP preclearance facilities should be considered as domestic flights when assessing the need to clear security at a US airport.
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Do you need to clear security when transiting in a US airport?
From | |||
Flights | International | Domestic | |
Onto | International | Yes | No |
Domestic | Yes | No | |
Do you need to clear security when transiting at a Schengen airport?
From | ||||
Flights | Schengen | US & UK | Other non-Schengen | |
Onto | Schengen | No | No* | Yes |
US & UK | No | No* | Yes | |
Other non-Schengen | No | No* | Yes | |
*Varies based on airport facilities and airlines
Airline factors
Another factor that often determines whether a passenger needs a security check is the type of ticket and carrier. Travelers on two separate tickets, or self-transiting, would likely need to check in again, meaning leaving the secure airside area and going through screening again. Some airlines, especially when the two flights are operated by different carriers in different terminals under codeshare or interline agreements, require additional checks as well.
Sometimes, the lack of necessary agreements that would require checked luggage to be collected and rechecked. For example, Air France sells itineraries with a stopover in Shanghai Pudong, the base of their partner China Eastern, but passengers are required to recheck their luggage and, therefore, go through security again after arriving via Air France or KLM flights. This is required even if the journey continues into another country, similar to the rules in the US.
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Airport layout and facilities matter too
Other than the aforementioned general rules and airline factors, the varying capability for an airport to process transit passengers can also create the need for security. Some airports do not have the ability to separate arriving flights and therefore, all passengers get funneled through security before entering the airside area again. Amsterdam Schiphol did not separate non-Schengen flights by security standards as it does now until ditching a decentralized security system in 2016.
Some airports adopt a decentralized airport security system, with the screening done at each boarding gate before departure to optimize the transit process. The best-known example is Singapore Changi Airport terminals one through three, where security is done at each gate right before boarding. This means all passengers connecting, regardless of destination or origin, need to be screened again prior to boarding their next flight.
Photo: Feylite | Shutterstock
Airports in India are also infamous for their ability to facilitate easy transfers. Double security checks are currently in place, meaning travelers connecting from a domestic flight to an international one need to go through screening, unlike in most other countries. Security checks are also required for some domestic-to-domestic connections in the country, making the process especially inconvenient.
To conclude, travelers generally should expect security when transferring if they are traveling into the airport on an international (non-Schengen for Europe) flight, with a few exceptions, such as from the US and UK into the EU. To be sure, passengers are advised to check with their airlines and airports for the exact rules.
