Aviation industry and airlines are undergoing hard times due to the SArS COVID-19 pandemic period as well as the tragedy of the heroic rebuff of Ukraine to the fascist–russist full-scale warfare invasion.

The current circumstances require indispensable measures to be taken in the major macroeconomic airline industry components. The presented paper is dedicated to the simplest macroeconomic problem setting in the framework of the

Nevertheless, some important problems are neither included within nor converge into those classes of the simplest macroeconomics models:

A combination of macroeconomics models incorporating the principle of the subjective entropy maximum is tried in the present work. The principle was developed during 1990–2010. Although this principle formally hardly deviates from the

Let us consider a macroeconomics problem by

The production function is given by the expression:

where _{t} +1 is the production function _{t}_{t}_{t}

For some reasons, the power indices of

For the components of _{t}_{t}

The division envisaged by eq. (3) is provided with the use of the individuals’ subjective preferences π:

The objective functional for the individuals’ subjective preferences

where

is the subjective entropy of the individuals’ subjective preferences _{π}

Then, on condition of

it is possible to find

This yields

Thus,

On the other hand,

This yields

Thus,

The procedure outlined in eqs (7)–(13) leads to the expression:

The normalising condition, i.e. eq. (14), means that

Because of eq. (15),

In turn

In the simplest case, the recursive system could be used:

For the accepted data:

The initial conditions would then be represented by:

and

The results of the computer simulation are shown in Figs 1–3.

In the case when

the picture drastically changes.

The results of modelling for eqs (1)–(20) with eq. (22) instead of eq. (21) are illustrated in Figs 4–6.

The results of calculations obtained in pursuance of eqs (1)–(22) are portrayed in Figs 1–6, and they prompt a conclusion that there must be some preferences function value that ensures neither decrease nor increase of the characteristics, but stable magnitudes.

Indeed, at the value of

there is a situation of stability.

The results indicated by eq. (23) prove the supposition described above. It is represented in Figs 7–9.

Moreover, at the value of

there is one more situation of stability.

The results arising pursuant to eq. (24) are shown in Figs 10–12.

Thus, there are at least two situations of the stability; and moreover, at practically the same production (compare Figs 7 and 10), the distribution between the components of _{t}_{t}_{t}

The other decrease is for the values of

For instance,

The results are represented in Figs 13–15.

Therefore, we have arrived at a means to formulate an optimisation problem for the production maximum.

One way in which the development of the model can be linked with the results following from eqs (1)–(26) arises when the preferences are considered not constant.

For example,

The initial value is given as:

For the parameter,

The computer simulation results arising pursuant to eqs (27)–(29) are shown in Figs 16–20.

It is discernible from the results of the simulation that, when the preferences functions obtained the values belonging to the diapason from eqs (23)–(24), the production and its characteristic components increase (see Figs 1–20).

It is supposed that the parameters of the income (the result of production)

Moreover, consumption _{min} or

The logistic function is a good one for a description of similar processes.

In such a problem, setting consumption

The problem is that consumption

The

When consumption _{min}. There is the so-called slavery labour that enables the sustenance of this relation.

If consumption _{max}, and this could be obtained through the constraint for physical capital

In the framework of the above constraints, the dynamical model has been constructed, which realises some properties of the process:

There is some value of the labour

On the other hand, there are some values ensuring the increase of the economical characteristics.

Also, it is a very important moment when the labour

Qualitative investigations based on the

It is important to bear in mind that the procedures outlined in the present study need not be confined in their scope to the choosing of the values of the preference function occurring in the examples discussed herein; rather, the preference functions are obtained in the explicit view following from the optimisation. In the examples discussed here, it is possible to show the change in the subjective entropy of the processes. This would explain the behaviour of the processes under study in the article but it could be further elaborated in further research.

At the current stage, studies into the creation of the macroeconomics classes of models, as well as their qualitative and quantitative investigations, are still underway. In addition, the applicability of these ideas extends predominantly to the higher educational issues.

The seminal feature is the production of the scientific product, which relates mostly to the intellectual product rather than equipment. Production of ‘discovery’ that can be evaluated though the years ahead is the peculiarity of such kind of human activity.