SwiftUI not updating based on @StateObject

Question

I am new to SwiftUI. I am trying to update an array of mockFlights (in this case as a dummy test just at index 0 for departureAirportIata:) with a string from the TextField. The data are displayed from the array as they should and when using button "Submit" with print statements, the viewModel.flights gets updated but the view never changes.

I have a model with mockData:

import Foundation


struct Flight: Identifiable, Equatable {
    
    let id = UUID()
    
    var departureAirportIata    : String
    var arrivalAirportIata      : String
    var departureAirportIcao    : String
    var arrivalAirportIcao      : String
    
    var numberOfDayLandings     : Int
    var numberOfNightLandings   : Int
    
    var aircraftType            : String
    var aircraftRegistration    : String
    var picName                 : String
    var sicName                 : String
    var remark                  : String?
    
}

struct MockData {
    static var mockFlights = [
        Flight(departureAirportIata: "WRO", arrivalAirportIata: "PRG", departureAirportIcao: "EPWR", arrivalAirportIcao: "LKPR", numberOfDayLandings: 2, numberOfNightLandings: 0, aircraftType: "B738", aircraftRegistration: "OK-UTH", picName: "SELF", sicName: "EVA"),
        Flight(departureAirportIata: "LGW", arrivalAirportIata: "OSL", departureAirportIcao: "EGKK", arrivalAirportIcao: "ENGM", numberOfDayLandings: 1, numberOfNightLandings: 0, aircraftType: "B738", aircraftRegistration: "OK-ILS", picName: "SELF", sicName: "PETR", remark: "DLY: 81, CTOT 1950"),
    ]
}

ViewModel with the following code:

import SwiftUI

class FlightVM : ObservableObject {
    
    
    @Published var flights : [Flight]
    
    init() {
        let flights = MockData.mockFlights
        self.flights = flights
    }
   
}

Parent view:

import SwiftUI

struct FlightsOverView: View {
    
    @StateObject var viewModel: FlightVM
    
    
    var body: some View {
        NavigationStack {
            List(viewModel.flights, id: \.id) { flight in
                NavigationLink(
                    destination: FlightDetailView(flight: flight), label: {
                        FlightCell(flight: flight)
                        .listRowInsets(EdgeInsets(top: 5, leading: 8, bottom: 5, trailing: 8))
                    })
                
            }
            .listStyle(PlainListStyle())
            .navigationTitle("Flights")
        }
    }
    
}

And childview:

import SwiftUI

struct FlightDetailView: View {
    @State var flight : Flight
    @StateObject var viewModel = FlightVM()
    
    var body: some View {
        
        NavigationView{
            Form {
                Section(header: Text("Flight Info")){
                    Text(flight.aircraftRegistration)
                    Text(flight.aircraftType)
                    Text(flight.arrivalAirportIata)
                    Text(flight.departureAirportIata)
                    TextField("Departure airport", text: $flight.departureAirportIata)
                }
                
                Button("Submit", action: {
                    viewModel.flights[0] = flight
                    print(viewModel.flights)
                    print(flight)
                    
                })
            }
        }
        
    }
    
}

The data are displayed from the array as they should and when using button "Submit" with print statements, the viewModel.flights gets updated but the view never changes.