There has been no civilian aircraft in the sky over Ukraine since early Thursday morning.
With the attack of the Russian military, the airspace was closed.
A huge problem would be if flights over Russia soon had to be stopped as well.
Deutsche Lufthansa announced that it would suspend the connection to Lviv in western Ukraine, and the group – like other airlines – had not headed for Kiev and Odessa since the beginning of the week.
Dramas take place not only in the air, but above all on the ground: Plant manufacturer Krones had to react quickly on Thursday night.
"We had already taken precautions and provided all-terrain vehicles," said CEO Christoph Klenk.
The S-Dax company is carrying out a project with Ukrainian and European employees in the south-west of Ukraine near the Hungarian border.
They got in touch by phone during the night and immediately brought the ten European employees overland from the Ukraine.
The manufacturer of filling and packaging systems has branches in the Ukraine and Russia to carry out installation and maintenance of the systems.
For Krones, Russia, Belarus and the Ukraine account for just 1.5 percent of sales.
In addition to Krones, many other German companies and sectors are directly affected by the Ukraine war because they have locations there or in Russia, employ people or are heavily dependent on supplies.
This applies to medium-sized export champions like Krones, but also to corporations like Volkswagen or Metro.
For which companies and sectors are the direct consequences particularly tangible?
Metro sends employees home
The wholesaler Metro employs 3,400 Ukrainian workers in the Ukraine and achieved sales of 800 million euros in its 26 wholesale stores there in the past financial year.
Metro closed 16 of the stores today and asked employees to stay at home.
Metro operates many more stores in Russia: With its 93 Russian stores, the company achieved sales of around 2.4 billion euros in the past financial year.
The group procures most of its groceries there from local production.
Russia is an important location for the wholesaler.
The concern is also great in the Volkswagen Group, which operates the largest factory in Russia of all German car manufacturers, the plant in Kaluga southwest of Moscow.
Around 4,000 employees build models there such as the VW Tiguan, the Polo and the Skoda Rapid.
Together with the second, smaller location in Nizhny Novgorod east of the capital, which VW operates with a partner, around 170,300 vehicles recently rolled off the assembly line in the country.
According to the company, Russia is also an important European market and production location for Mercedes.
Three years ago, the then head of the group, Dieter Zetsche, together with the Russian ruler Vladimir Putin, opened the first Mercedes plant in Russia, which is designed for more than 1,000 employees.
Zetsche's successor, Ola Källenius, was cautious about the war in Ukraine at the press conference on Thursday.
"On a day like this, our thoughts are with the people," he said.
It's not about the economic aspects.
Karl Haeusgen, President of the Association of Mechanical and Plant Engineers (VDMA), became clearer.
He supports tough sanctions against Russia, although he believes they will have an impact on the export-heavy industry he represents.
The VDMA cannot yet assess how serious the consequences will be.
The agricultural machinery manufacturer Claas does not want to speculate either.
The group has had a plant in Krasnodar, Russia, since 2005, where more than 700 employees produce around 1000 combine harvesters a year or assemble large tractors.