diff --git a/libraries/AP_NavEKF3/AP_NavEKF3_VehicleStatus.cpp b/libraries/AP_NavEKF3/AP_NavEKF3_VehicleStatus.cpp
index 2effc2d932..f6dac0b8ff 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3_VehicleStatus.cpp
+++ b/libraries/AP_NavEKF3/AP_NavEKF3_VehicleStatus.cpp
@@ -305,7 +305,7 @@ void NavEKF3_core::detectFlight()
 
     if (assume_zero_sideslip()) {
         // To be confident we are in the air we use a criteria which combines arm status, ground speed, airspeed and height change
-        float gndSpdSq = sq(gpsDataDelayed.vel.x) + sq(gpsDataDelayed.vel.y);
+        float gndSpdSq = sq(gpsDataNew.vel.x) + sq(gpsDataNew.vel.y);
         bool highGndSpd = false;
         bool highAirSpd = false;
         bool largeHgtChange = false;
@@ -318,8 +318,9 @@ void NavEKF3_core::detectFlight()
             }
         }
 
-        // trigger at 10 m/s GPS velocity, but not if GPS is reporting bad velocity errors
-        if (gndSpdSq > 100.0f && gpsSpdAccuracy < 1.0f) {
+        // trigger on ground speed
+        const float gndSpdThresholdSq = sq(5.0f);
+        if (gndSpdSq > gndSpdThresholdSq + sq(gpsSpdAccuracy)) {
             highGndSpd = true;
         }
 
@@ -330,7 +331,7 @@ void NavEKF3_core::detectFlight()
 
         if (motorsArmed) {
             onGround = false;
-            if (highGndSpd && (highAirSpd || largeHgtChange)) {
+            if (highGndSpd && (expectTakeoff || highAirSpd || largeHgtChange)) {
                 // to a high certainty we are flying
                 inFlight = true;
             }
diff --git a/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp b/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp
index 9c8be48b29..6afc0a1143 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp
+++ b/libraries/AP_NavEKF3/AP_NavEKF3_core.cpp
@@ -896,6 +896,15 @@ void NavEKF3_core::calcOutputStates()
         posOffsetNED.zero();
     }
 
+    // Detect fixed wing launch acceleration using latest data from IMU to enable early startup of filter functions
+    // that use launch acceleration to detect start of flight
+    if (!inFlight && !expectTakeoff && assume_zero_sideslip()) {
+        const float launchDelVel = imuDataNew.delVel.x + GRAVITY_MSS * imuDataNew.delVelDT * Tbn_temp.c.x;
+        if (launchDelVel > GRAVITY_MSS * imuDataNew.delVelDT) {
+            setTakeoffExpected(true);
+        }
+    }
+
     // store INS states in a ring buffer that with the same length and time coordinates as the IMU data buffer
     if (runUpdates) {
         // store the states at the output time horizon