It may spoil an entertaining deliberate confusion, but you know the airports with the jets, and the cities full of immigrants, were clearly stated as separate from the start: "two sources of corruption ... the first ... the second".
Immigrants were explicitly linked to supposed airport-induced measurement error "as population goes up due to immigration...jet travel goes up and this causes more traffic which warms the air at these weather stations" in the original post and doubled down on by these immigrants supposedly being "a primary driver of data difficulties in climatology". I found it amusing that the example posed was a RAF base...
"be reasonable, meet them halfway."