Airports are a source of economic prosperity, but the main airports in many cities are reaching the limits of their capacity. Faced with the difficulty of expanding them, the development of multi-airport systems may be a mechanism for adapting to the pressure of demand. However, multi-airport systems are difficult to develop, as there is no clear typology and they depend on local particulars. On the other hand, and perhaps more relevantly, airlines have few incentives to operate at secondary airports. In a liberalized market, airlines will always tend to concentrate their activity on main airports. In this article, we present these basic principles of functioning that make multi-airport systems a difficult balance, although an interesting one to try to achieve.

The main aim of this article is to explain how a computer process, the «Blockchain» or chain of blocks, can generate the necessary trust for the creation, acceptance and increasingly widespread use of digital currencies, under a new concept or paradigm of money not maintained by any state or supranational entity: cryptocurrencies. In order to understand this process, the technical aspects of how the blockchain operates and how it has managed to generate confidence in the end user are explained first. Secondly, its implementation will be analyzed through the best known of all, Bitcoin, and through the data related to the expansion and use of the main cryptocurrencies in a market that in the last two years has multiplied by 65, reaching half a trillion dollars. This work closes by exposing the main conclusions and reflections.

The banking industry is facing a major transformation of its activity due to the need to reinvent its services (which are expensive and not designed for online use), the change in user demand for digital products and the need to adjust inefficient structures. Traditionally the financial sector has been almost exclusively an area for financial institutions, but the falling cost of technologies has led to the emergence of new players in the industry, such as fintechs, with alternative proposals in all spheres of financial activity, through new mobile-first and data-driven formulas. However, after a few years, most of these new companies experience scalability problems and, going against their original philosophy, they end up collaborating with banks, generating a partnership of mutual interest: fintechs contribute to the transformation of the bank, and with the support of the bank, they achieve growth that they would not achieve alone. Through these banking-fintech partnerships, a paradox arises in that these entities which initially challenged the banks may end up being their point of support, ensuring the change to the banking sector is quicker and more transformational than disruptive. Conversely, the fintechs that remain in competition with the banks (between 20% and 25%) are forced into mergers, agreements, etc. in order to break-even. In Spain, the growth problems in these areas of competition with the banks (robo-advisors and crowdlending) seem even more intense than in other countries.

The most significant problem for banks comes from the large tech operators that have the capacity to unseat financial institutions in some of the most profitable spheres of activity. It seems impossible for banks to maintain total control of the business in the spheres that are shared with tech operators, such as purchase payments and money transfers. However, banks have an advantage in terms of their widely-recognised customer data protection management, which is a value in which they clearly exceed the fintechs.

Banks are developing multiple agreement strategies with fintechs, such as direct purchases, acceleration and incubation programmes, venture capital funds, service agreements and partnership agreements. Proper analysis of each area of innovation is crucial to identify the contributions made by a fintech, and the key variables are the capacity to generate volume and ability to displace current banking services. This article proposes a relationship model consisting of the gradual integration of fintechs into banking environments through: i) integration into the core of the bank; ii) collaboration or service agreements; iii) contributing to their development through acceleration and incubation programmes and the launch of “challenger” programmes or competitions to discover talent.

This article analyses the sustainability of the monetary system, with a systemic focus based in complex thinking. This thinking is far removed from the simple and the conventional, considering not only the distinct actors involved in the system but also the relationships and interactions between them. It is a way of thinking that views systems not as static or permanent, but as dynamic equilibriums linked to adaptation and change.

Being a socio-ecological system, the monetary system is subject to the dynamic behaviour of an adaptive cycle, which in turn is part of a panarchy of systems drawn to different scales across space and time. It is only when one considers this nested network of interconnected systems that it is possible to ensure the sustainability of each system individually and of the group as a whole.

The current monopoly of money in the form of bank debt has reached a point where it is so rigid and centralized it has become unsustainable. Proof of this can be seen in the systemic crisis we are currently living in. From a systemic focus based in complex thinking, this article analyses how the introduction of complementary currencies into the monetary system is one way in which its sustainability can be improved, also contributing to the sustainability of the planetary system as a whole, both economically and environmentally.