On April 3rd, I have an appointment to obtain German citizenship, and on April 8th, I am flying to Poland for a work trip.
As part of the naturalization process, I will need to relinquish my permanent residence card for Germany. This means I will not have enough time to obtain a German ID card or passport before my departure to Poland. I do have color photocopy of residence permanent which is still valid till 2033.
After April 3rd, I will hold dual citizenship and still possess a valid passport from my original country. However, this passport would normally require a visa for travel to both Poland and Germany from outside the EU. Since I will have given up my permanent residence, I will have no proof of a visa.
Unfortunately, postponing my citizenship appointment is not a viable option, as I have several travel plans outside the EU after I return. Delaying the process further would also mean that my security clearance would expire, requiring another security check before I can get my citizenship. Therefore, this timing is ideal—except for the conflict with my trip to Poland.
I am aware of the express passport option in Germany but this is still risk it will not arrive in time.
According to Wikipedia:
For flights within the Schengen Area (either between Schengen member states or within the same Schengen member state), law enforcement agencies, airport authorities and air carriers are permitted only to carry out security checks on passengers and may not carry out border checks.[Such security checks can be conducted through the verification of the passenger's passport or national identity card
https://en.wikipedia.org/wiki/Schengen_Area
If this information is accurate, I should be able to travel without a visa. I will be flying with LOT Polish Airlines. Based on my past experiences, including recent flights to Lithuania with Lufthansa, my passport and visa status was not checked, and my permanent residence permit was not required.
Would it be possible to fly to Poland and back without presenting my Visa or should there be anything I should be concerned about?
Update
I successfully travelled from Germany to Poland and back without a visa. Airline only asked for identification which my foreign passport was sufficient as long as it was not expired.