# Emerging Technologies in Transportation Casebook/Immigration Processing
## Introduction

On average, 2,900,000 passengers fly daily in and out of airports in the U.S.. Today, the airline industry is one of the biggest industries in the U.S., with more than 10 million scheduled passenger flights yearly. Built in 1928, Newark Metropolitan Airport became the first commercial airport in the U.S to provide services to people after the 1925 Air Mail Act commercialized the usage of air travel. With the surge of the airline industry during the 1960s, massive airports like Washington DC’s Dulles were built to accommodate the growing industry. As the airline industry continues to grow, the need for improved security and streamlining of airport services has led airports to look toward technologies like biometrics to solve their problems.
Biometrics cannot be considered to be a new form of technology. In 1892, Sir Francis Galton developed a fingerprint classification system that would be regarded as the foundation of biometrics. Since the 20th century, biometrics have been used for multiple purposes, including immigration processing and law enforcement. With the September 11 terrorist attacks, airport security became a massive priority for all airports. To meet those security challenges, the Transportation Security Agency (TSA) turned toward biometrics as the next step in airport security.
Improving airport services has always been a challenge for all airports. To improve services, airports began automating baggage claim, and boarding processes as well as airport operations such as sanitation. Automating services allow airports to streamline their services, therefore improving their overall service quality.
Despite the massive benefits biometrics and facial recognition technology provide airports, privacy concerns remain an enormous barrier to technological development. Among the challenges, one of the largest is the mass implementation of the technology, which is still in its testing phase.
This casebook was created by Jimmy Luong and Valentina Farias on November 2022 as part of Dr. Jonathan Gifford's CEIE 690/POGO 750 Emerging Technologies, Transportation, and Public Policy class at George Mason University's Schar School of Policy and Government.

## Security
#### Use of Biometrics in the United States

According to the International Biometrics Identity Association (IBIA), biometrics are defined as an “automated method for verifying or identifying the identity of a living individual based on physiological or behavioral characteristics”. When passing through airport security, every person is required to show identification. Currently, most people will use a form of physical ID such as their driver's license or passport. Biometrics, on the other hand, use digital IDs. According to the TSA, a digital ID is hosted on a digital platform — often a user's mobile device — owned and managed by an issuing authority”. Examples of digital ID include digital copies of a driver’s license or passport. To verify a digital ID, TSA uses Credential Authentication Technology (CAT) with Camera and 1:1 facial verification technology (CAT-2). CAT-2 serves two functions; the first is to verify the authenticity of the digital ID, and the second is to identify imposters and illegal immigrants by using facial verification technology that matches the traveler’s face with a face previously captured image from the database. This technology is still being tested by a few airports in the in U.S. at Detroit (DTW) and Atlanta (ATL) Airports. Overall, the popularity of the technology has increased in other countries like Japan and organizations like the International Air Transport Association (IATA) or Star Alliance have their own biometrics program.

#### Using Biometrics - Step-by-Step Process

Step 1: A sign will direct a person to a security checkpoint to provide digital ID verification. Another sign will lead them to a different security checkpoint to verify their physical form of ID.
Step 2: The Traveler presents their digital ID on a mobile device to the TSA officer at the security checkpoint, who will then use the CAT-2 system to examine the ID given.
Step 3: The traveler’s mobile device will request that the traveler show TSA their digital ID. Once the passenger consents, the digital ID is submitted to CAT-2.
Step 4: CAT-2 takes a live picture of the passenger to match the live picture from the digital ID.
Step 5: Once CAT-2 verifies the person’s identity, the system will examine other information such as flight Status, ID authentication, and itinerary information by verifying the digital ID from the Issuing Authority."
Step 6: Once CAT-2 confirms the passenger's identity, the TSA officer will direct the passenger to the next step of the security process. If there is a no-match outcome, the TSA officer will ask for another ID to verify the traveler’s identity.

#### Factors that impact the development of biometrics

The use of biometrics can be considered to be the next step of airport security since it advocates for the transition from a physical ID to a digital ID. The most significant benefit of biometric technology is that it allows passengers to use a physical or digital ID. Additionally, with increased user-friendliness, biometrics offer a more efficient method of identity verification. This is due to a high level of information acceptability and collectability. IATA says biometric security reduces human error in checking passports. Another benefit is that the technology assists TSA officers in analyzing and checking the Department of Homeland Security's entire fingerprint database to check if a person is attempting to use a fraudulent ID.
Despite the benefits that biometrics bring, privacy concerns remain the most prominent barrier to the mass deployment of a biometrics program in the United States. According to a 2019 survey by IATA, it was found that “73% of passengers are willing to share their biometric data to improve airport processes (up from 46% in 2019). TSA is currently working on a system to manage information known as the “OTVC Document Management Systems (DMS)” or known as “the Gateway”. There is still work to be done regarding who can access the information, where the information will be stored, and when this information will be used. Despite the positive reactions from the public, IATA also found that “Data protection remains a key issue with 56% of passengers indicating concern about data breaches. Passengers want clarity on who their data is being shared with (52%) and how it is used/processed (51%).”. Technical concerns remain a problem as the technology may stop working or break at any moment. As a result, passengers will be required to go through a different gate that only provides service with physical ID until the system is back online or is replaced.
As a result of the challenges stated above, TSA has made program participation voluntary and is still testing the technology.

## Operations

Airports, which are often considered the gateway to cities, have faced increasing volumes of passengers in the last few years. Even with the COVID-19 pandemic, which temporarily shut down commercial air travel for many countries, travel demand is once again on the rise. Countries like Colombia, Mexico and Nigeria have already reached their pre-pandemic passenger traffic demand in 2022. The Airports Council International (ACI) also predicts that global air travel demand will reach 2019 levels by 2024. High travel demands often push airports to their capacity, leading to crowded airports and long security checks. This causes passenger frustration and stress, making the overall experience unpleasant, and at times, dissuading passengers from returning to that airport.
High passenger volumes means that airports will need to implement solutions like smart gates, smart check-in processes, and biometric technology to improve passenger experiences and accelerate security queues. These digital solutions will improve the commercial and technical efficiency of airports, ensuring they remain competitive while providing safe and welcoming environments for passengers.

#### Self-Service Technology (SST)

One way airports can become more efficient is through Self-Service Technology (SST), which allows airports to automate processes like flight and baggage check-in and parking. SST can speed up processes and reduce queues at the check-in counter as some passengers will check-in online. Allowing customers to access their flight information through smartphones also gives airlines a convenient method of communicating and interacting with customers. It takes two minutes for a passenger to check in using the traditional method while some self-service check-in systems have sped up this process to 30 seconds, making it four times faster than the traditional check-in method.
There are many strategies to integrate technology in airports. The Munich Airport employed a “mobility as a service” program that allows passengers to compare transportation options to travel to and from the airport and see real-time waiting times at checkpoints. The Copenhagen Airport uses SST solutions to reduce waiting times during boarding and baggage claim. Singapore’s Changi Airport has digitalized its identity, supporting customers through apps; and using IoT, AI, and machine learning to engage with customers at various stages of their journey. This allows them to have many digital platforms which can be accessed through One ID – allowing the airport to collect data, and the customer to receive highly personalized experiences, information and offers. Changi Airport has won over 654 awards, including UK Business Traveler’s Best Airport in the World 35 times.
Taufik & Hanfiah’s 2019 study determined that passengers tend to value SST’s “perceived usefulness” over its “ease-of-use”. This means that passengers will use the technologies if they deem them useful, or faster, but airport management should ensure that SST are simple and easy to use. SSTs are becoming more common in airports across the globe and are one step that airports can take to reach digital maturity, that is, full integration of intelligent systems in their management and operating systems.

#### Automated Border Control (ABC) / e-Gates

Automated Border Control (ABC), often referred to as e-Gates, are fully automated systems that authenticate travel documents and corroborate traveler identity. The ongoing use of biometric technology and travelers’ acceptance of SSTs have led to the use of ABCs in airports.
ABCs are useful as security agents often have a very short amount of time to determine whether the passenger in question is admissible into the country or not according to their immigration policies. Many ABCs use tokens to track travelers. When the passenger is located for the first time, a token will be created. The token will remain active until the passenger passes through an immigration checkpoint again. The token will rely on face recognition to determine if it is the same traveler. ABCs also rely on databases that store passenger information and travel history as well as machine-readable travel documents. These documents include biometric passports and e-passports with radio frequency identification (RFID) chips that store personal data and varying biometric traits such as fingerprints, face, and iris images. Systems like these facilitate high volumes of passengers while maintaining security and meeting immigration requirements.
ABC structures include the electronic passport reader, biometric readers, an electronic door which allows the passenger to pass through, a screen that displays visual instructions, and several biometric capture devices. There are three main types of ABCs, single-step, integrated and segregated two-step systems. Single step processes are those where the traveler only needs to verify their identity at the e-gate and does not need to enroll prior to the use of the gate. The reading of biometrics and authentication occurs simultaneously. In the case where there is an error or the information does not match, the traveler will have to see an immigration officer to undergo the traditional check. Integrated two-step systems split the document check and identity verification into two steps within the same physical space. Segregated two-step systems are the same as integrated two-step systems but occur at two separate locations.
According to the biometric data, previous travel history and behavior, travelers will be categorized into different risk categories, known, normal and enhanced passengers. Each category has different levels of security checks. Known travelers will undergo previous background checks, and after passing, will have access to expedited checks. This trusted-traveler program is only possible given the high levels of accuracy of biometric systems. In the United States, there are different programs that give “known” travelers the convenience of faster checks. They include Global Entry, Nexus, Sentri, and TSA PreCheck. By allowing “known” travelers to proceed faster, it also frees resources to screen other travelers who pose a higher risk. Enhanced passengers will experience the most screening.
For digital transformations to be successful, it is necessary to invest in human resource education and training. Each employee should understand why digitization is important and the benefits they will receive from it. Creating a culture of digitization will also mean that employees will be able to anticipate needs and skills required. It is also important to have a high degree of cooperation between the airport, airlines, and different levels of government.

#### Challenges

Although SSTs and ABCs are needed to expedite airport processes, there are still some challenges that need to be addressed. Acceptance of new technologies varies depending on age groups, with younger generations accepting technological changes faster, and adapting more easily. Taufik & Hanfiah argue that in addition to new technologies, airports should maintain a traditional check-in counter for those who prefer human interaction or do not wish to learn how to use the self-serving counters.
Like many other technological equipment, SSTs and ABCs can break or stop functioning. If this happens, a back-up machine will need to be used, or the previous, traditional process can be used until the SST or ABC is fixed. Many airports are also in the early stages of digitization, and thus, are not prepared to become “smart” yet. Digitizing includes new security procedures, training, and new equipment. Nonetheless, it is important for airports to adopt new technologies to stay competitive.
On occasion, travelers have tried to fool automated systems using “photo attacks” where a person will use someone else’s photo rather than their own face to fool the face recognition system. Similarly, masks with photos printed on them have been used for similar purposes. The use of makeup, costumes, wigs, and plastic surgery also make it more difficult for the face recognition system to identify travelers.

## Effects of COVID-19 on Airport Operations

The COVID-19 pandemic, which significantly reduced air traffic in 2020 and 2021, presented challenges in sanitation and health certificate checks, but also provided opportunities to further digitize processes, reduce touchpoints, and improve security in airports.

#### Digital Health Certificates

To stop the spread of COVID-19, many governments required travelers to show proof of vaccines or negative PCR tests to be eligible to enter the country. Initially, many of the vaccine certificates were paper documents which increased processing times at airports. The International Air Transport Association (IATA) released data that showed that at 30% pre-COVID travel demand levels, processing times had risen from 1.5 to 3 hours. At that same pace, if travel demand recovered to 100% pre-COVID traffic levels, processing times would increase to 8 hours.
IATA also recommended required health certificates to be integrated into the automated system through a digital certificate. This would reduce processing times and queueing. The digital certificates need to meet a standard so that they are internationally recognized and are interoperable with testing facilities and other vaccine certificates. IATA identified other advantages of digital health certificates, these included reducing touchpoints with the removal of physical documents, increasing the capacity of border control authorities who would only need to manage one digital identity, and avoiding the use of fraudulent documents.
Digitizing health certificates aligned with previous moves to give passengers control over their journey through SSTs. Digital health certificates enabled travelers to arrive at airports “ready to fly” as they had been used to, instead of forcing them back to traditional check-in processes.

#### Sanitation

COVID-19 presented airports with the opportunity to enhance their cleaning procedures and create safer environments for travelers. Many airports have risen to the challenge and have developed different ways to sanitize their space. Kováčiková et al. identify the following approaches:
* Qatar’s Hamad International Airport in Doha, invested in “Smart Screening Helmets” which are worn by airport employees to protect them from the virus. In addition, the airport also deploys UV disinfection robots that emit UV-C light eliminating viruses. These robots are placed in strategic areas with high volumes of travelers.
* Singapore’s Changi International Airport also deployed autonomous cleaning robots with UVC LED technology and disinfecting sprays.
* Vancouver International airport uses ultraviolet cleaning lamps and contactless screen protectors in kiosks.
* Houston International Airport also uses autonomous robots to clean and disinfect surfaces using UV technology and LIDAR remote sensing to determine the distance of the target objects.
* Rome’s Fiumicino International Airport uses thermal scanners and smart helmets with infrared temperature sensors to measure travelers’ body temperature.

## Looking Ahead
#### ACI’s Smart Security

The Airports Council International (ACI) “represents the collective interest of airports around the world to promote excellence in the aviation industry”. They do so by working with governments, experts, and international organizations like ICAO, IATA, and WHO to develop standards, policies, programs, and best practices globally. ACI currently represents 1950 airports, and 717 members in 185 countries.
ACI has determined that by 2040, international passenger traffic will be almost at par with domestic traffic. International passenger traffic will increase from 41.4% in 2017, to 48.6% in 2049. To tackle these high travel demands, ACI has developed Smart Security as the “leader in security innovation for passenger and baggage screening” and envisions checkpoints as “walk-through walkways”.
ACI identified airport design as a problem that needs to be solved. They claim that security measures are usually reactionary and are not considered during the design process. They also worry that current airports do not have the capacity to provide service for future passenger traffic. ACI expects 20.9 billion passenger traffic in 2040.
To tackle this problem, ACI partnered with airports, government agencies and airlines to strengthen security, increase operational efficiency, and improve passengers’ experience. Airport partners include the Amsterdam Airport, London Heathrow, Singapore’s Changi Airport, and Hamad International Airport Qatar. Government agency partners consist of the UK’s Department of Transport, the US Transportation Security Administration, Transport Canada, Canadian Air Transport Security and New Zealand’s Aviation Security Service. This global partnership also includes KLM, Lufthansa, Qantas, and AeroMexico as airline partners.
Ultimately, Smart Security will introduce risk-based security concepts through artificial intelligence, automated threat recognition, and global information sharing. It will also advance screening technologies that take up less physical space and develop process innovations that allow passengers to have a seamless walking experience while going through different security checkpoints. From the traveler’s perspective, the journey will be a non-intrusive, walking-pace experience. The Smart Security program has pioneered research and proposed many of today’s current practices, like automated tray return systems and central image processing that allows x-ray images to be reviewed in separate rooms. Current research is focused on explosive detection systems for cabin baggage (EDS-CB) and computed tomography (CT).

#### Airport 4.0

The concept of Airport 4.0 represents the full digitization of airports and full digital maturity. Traditional airports with basic IT solutions are considered Airports 1.0. Airports that include some automation, SSTs, and Wi-Fi are classified as Airports 2.0. Airports in the next phase, Airport 3.0, are fully automated. Finally, Airport 4.0 are smart airports, which are fully digitized, and data is captured and shared with key stakeholders. Airport 4.0 are part of a wider digital ecosystem.
The digital transformation associated with Airport 4.0 not only automates processes but also engages passengers through smartphones, cloud, blockchain technology, big data, IoT, and robotics. These allow for fast solutions and preventive actions to take place using geo-location, identity management, flow management and RFIDs. To support full digitization, airports must provide pervasive, reliable, and secure broadband wireless connectivity.
Private companies are now bidding to become connectivity providers and provide better operational and situational awareness through intelligent application-based solutions. From automatically reporting incidents to first responder vehicles, to using digital twins, Airport 4.0 is the future of aviation.
Airport 4.0 will require collaboration between many stakeholders. To ensure that the collaboration is efficient, airports will need high levels of connectivity. Maintaining strong security, a reliable network, and keeping services and data management at the airport, will require high-performance LTE and 5G networks. Nokia’s Global Public Safety and Aviation Practice Lear, Richard van Wijk, stated that “connectivity can no longer be treated as a commodity. It is a strategic asset that is as important to an airport as the runway”. This concept is at the heart of the Airport 4.0 vision.

## Conclusion

In a post-9/11 world, the need for increased airport security has increased dramatically. To meet the growing security challenge, USA’s TSA turned to CAT-2, which combines biometrics and facial recognition technology to verify the validity of any form of digital ID and to verify the passenger’s identity. CAT-2 reduces human error and provides a more effective form of ID verification. Factors such as the usage, storage, and access to information have significantly slowed down the mass implementation of biometrics in the U.S, causing it to remain in testing. Other countries have strengthened security processes by using ABCs/e-Gates. ABCs use biometric technology to allow border control authorities to keep track of travelers and verify passenger identity.
Most airports today have employed self-service technology by allowing travelers to check-in using their smartphones or by providing flight information digitally. Although some travelers still prefer face-to-face interactions, most travelers are happy to use SSTs. The COVID-19 pandemic accelerated the use of technologies by digitizing and automating processes to avoid the spread of the virus.
Modern airports are shifting from places where planes take off and land to retail and hospitality hubs. They also represent the region’s economic development, and the most modern airports, like Singapore’s Changi airport, have become a landmark themselves. As more airports adopt new technologies and engage with travelers to make their journeys as seamless as possible, airports that do not digitize and automate will become less competitive.

## References

* ↑ Air Traffic By The Numbers. FAA. (2020, January 31). Retrieved November 13, 2022
* ↑ Air Traffic By The Numbers. FAA. (2020, January 31). Retrieved November 13, 2022
* ↑ Privacy Impact Assessment for the Travel Document Checker Automation - Digital Identity Technology Pilots. Department of Homeland Security. (2022, January 14). Retrieved November 13, 2022.
* ↑ Khan, N., & Efthymiou, M. (2021). The use of biometric technology at airports: The case of customs and border protection (CBP). International Journal of Information Management Data Insights, 1(2), 100049.
* ↑ Biometrics Technology | Transportation Security Administration. Retrieved November 13, 2022.
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* ↑ Khan, N., & Efthymiou, M. (2021). The use of biometric technology at airports: The case of customs and border protection (CBP). International Journal of Information Management Data Insights, 1(2), 100049.
* ↑ Biometrics Technology | Transportation Security Administration. Retrieved November 13, 2022.
* ↑ IATA. (2021, May 26). Digitalization Needed for Smooth Restart. IATA 2021 Press Releases. Retrieved November 12, 2022
* ↑ Biometrics Technology | Transportation Security Administration. Retrieved November 13, 2022.
* ↑ Sponsored: How biometric services are shaping the airport of the future according to NEC. IATA. (2020, January 31). Retrieved November, 13, 2022
* ↑ Office of Transportation Vetting and Credentialing Screening Gateway and Document Management System Privacy Impact Assessment. Department of Homeland Security. (2005, January 14). Retrieved November 13, 2022
* ↑ Sponsored: How biometric services are shaping the airport of the future according to NEC. IATA. (2020, January 31). Retrieved November, 13, 2022.
* ↑ The impact of covid-19 on airports-and the path to recovery. ACI World. (2022, October 6). Retrieved November 12, 2022.
* ↑ About ACI. ACI World. (2022, October 20). Retrieved November 12, 2022.
* ↑ Taufik, N., & Hanafiah, M. H. (2019). Airport passengers' adoption behaviour towards self-check-in kiosk services: The roles of perceived ease of use, perceived usefulness and need for human interaction. Heliyon, 5(12).
* ↑ Kováčiková, K., Remencová, T., Sedláčková, A. N., & Novák, A. (2022). The impact of covid-19 on the digital transformation of the airports. Transportation Research Procedia, 64, 84–89.
* ↑ Zaharia, S. E., & Pietreanu, C. V. (2018). Challenges in airport digital transformation. Transportation Research Procedia, 35, 90–99.
* ↑ Taufik, N., & Hanafiah, M. H. (2019). Airport passengers' adoption behaviour towards self-check-in kiosk services: The roles of perceived ease of use, perceived usefulness and need for human interaction. Heliyon, 5(12).
* ↑ Ivannikova, V., Shenchuk, D., Konovalyuk, V., Borets, I., & Vysotska, I. (2021). Estimation of the innovative technologies influence on passengers processing procedures at the Airport. Transportation Research Procedia, 59, 127–136.
* ↑ Zaharia, S. E., & Pietreanu, C. V. (2018). Challenges in airport digital transformation. Transportation Research Procedia, 35, 90–99.
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* ↑ Awards and accolades: Changi airport group. Awards and Accolades | Changi Airport Group. (n.d.). Retrieved November 12, 2022
* ↑ Taufik, N., & Hanafiah, M. H. (2019). Airport passengers' adoption behaviour towards self-check-in kiosk services: The roles of perceived ease of use, perceived usefulness and need for human interaction. Heliyon, 5(12).
* ↑ Morosan, C. (2016). An empirical examination of U.S. travelers’ intentions to use biometric e-gates in airports. Journal of Air Transport Management, 55, 120–128.
* ↑ Ortega, D., Fernández-Isabel, A., Martín de Diego, I., Conde, C., & Cabello, E. (2020). Dynamic facial presentation attack detection for Automated Border Control Systems. Computers & Security, 92, 101744.
* ↑ Ortega, D., Fernández-Isabel, A., Martín de Diego, I., Conde, C., & Cabello, E. (2020). Dynamic facial presentation attack detection for Automated Border Control Systems. Computers & Security, 92, 101744.
* ↑ Sanchez del Rio, J., Moctezuma, D., Conde, C., Martin de Diego, I., & Cabello, E. (2016). Automated Border Control e-gates and facial recognition systems. Computers & Security, 62, 49–72.
* ↑ Ortega, D., Fernández-Isabel, A., Martín de Diego, I., Conde, C., & Cabello, E. (2020). Dynamic facial presentation attack detection for Automated Border Control Systems. Computers & Security, 92, 101744.
* ↑ Sanchez del Rio, J., Moctezuma, D., Conde, C., Martin de Diego, I., & Cabello, E. (2016). Automated Border Control e-gates and facial recognition systems. Computers & Security, 62, 49–72.
* ↑ Sanchez del Rio, J., Moctezuma, D., Conde, C., Martin de Diego, I., & Cabello, E. (2016). Automated Border Control e-gates and facial recognition systems. Computers & Security, 62, 49–72.
* ↑ Kalakou, S., Psaraki-Kalouptsidi, V., & Moura, F. (2015). Future airport terminals: New technologies promise capacity gains. Journal of Air Transport Management, 42, 203–212.
* ↑ Morosan, C. (2016). An empirical examination of U.S. travelers’ intentions to use biometric e-gates in airports. Journal of Air Transport Management, 55, 120–128.
* ↑ Kalakou, S., Psaraki-Kalouptsidi, V., & Moura, F. (2015). Future airport terminals: New technologies promise capacity gains. Journal of Air Transport Management, 42, 203–212.
* ↑ Zaharia, S. E., & Pietreanu, C. V. (2018). Challenges in airport digital transformation. Transportation Research Procedia, 35, 90–99.
* ↑ Taufik, N., & Hanafiah, M. H. (2019). Airport passengers' adoption behaviour towards self-check-in kiosk services: The roles of perceived ease of use, perceived usefulness and need for human interaction. Heliyon, 5(12).
* ↑ Kováčiková, K., Remencová, T., Sedláčková, A. N., & Novák, A. (2022). The impact of covid-19 on the digital transformation of the airports. Transportation Research Procedia, 64, 84–89.
* ↑ Ortega, D., Fernández-Isabel, A., Martín de Diego, I., Conde, C., & Cabello, E. (2020). Dynamic facial presentation attack detection for Automated Border Control Systems. Computers & Security, 92, 101744.
* ↑ Kováčiková, K., Remencová, T., Sedláčková, A. N., & Novák, A. (2022). The impact of covid-19 on the digital transformation of the airports. Transportation Research Procedia, 64, 84–89.
* ↑ IATA. (2021, May 26). Digitalization Needed for Smooth Restart. IATA 2021 Press Releases. Retrieved November 12, 2022
* ↑ IATA. (2021, May 26). Digitalization Needed for Smooth Restart. IATA 2021 Press Releases. Retrieved November 12, 2022
* ↑ Kováčiková, K., Remencová, T., Sedláčková, A. N., & Novák, A. (2022). The impact of covid-19 on the digital transformation of the airports. Transportation Research Procedia, 64, 84–89.
* ↑ About ACI. ACI World. (2022, October 20). Retrieved November 12, 2022
* ↑ Smart security. ACI World. (2022, April 29). Retrieved November 12, 2022
* ↑ Smart security. ACI World. (2022, April 29). Retrieved November 12, 2022
* ↑ Smart security. ACI World. (2022, April 29). Retrieved November 12, 2022
* ↑ Smart security. ACI World. (2022, April 29). Retrieved November 12, 2022
* ↑ Smart security. ACI World. (2022, April 29). Retrieved November 12, 2022
* ↑ Kováčiková, K., Remencová, T., Sedláčková, A. N., & Novák, A. (2022). The impact of covid-19 on the digital transformation of the airports. Transportation Research Procedia, 64, 84–89.
* ↑ Zaharia, S. E., & Pietreanu, C. V. (2018). Challenges in airport digital transformation. Transportation Research Procedia, 35, 90–99.
* ↑ Airport 4.0: How private 5G is a key enabler. International Airport Review. (2021, November 1). Retrieved November 12, 2022.
* ↑ Airport 4.0: How private 5G is a key enabler. International Airport Review. (2021, November 1). Retrieved November 12, 2022.
* ↑ Nokia. (2021, August). The Time for Airports to Digitalize is Now. Nokia Newsroom. Retrieved November 12, 2022.
* ↑ Airport 4.0: How private 5G is a key enabler. International Airport Review. (2021, November 1). Retrieved November 12, 2022.
* ↑ Nokia. (2021, August). The Time for Airports to Digitalize is Now. Nokia Newsroom. Retrieved November 12, 2022.